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Sample records for welded ct specimens

  1. Study of residual stresses in CT test specimens welded by electron beam

    Science.gov (United States)

    Papushkin, I. V.; Kaisheva, D.; Bokuchava, G. D.; Angelov, V.; Petrov, P.

    2018-03-01

    The paper reports result of residual stress distribution studies in CT specimens reconstituted by electron beam welding (EBW). The main aim of the study is evaluation of the applicability of the welding technique for CT specimens’ reconstitution. Thus, the temperature distribution during electron beam welding of a CT specimen was calculated using Green’s functions and the residual stress distribution was determined experimentally using neutron diffraction. Time-of-flight neutron diffraction experiments were performed on a Fourier stress diffractometer at the IBR-2 fast pulsed reactor in FLNP JINR (Dubna, Russia). The neutron diffraction data estimates yielded a maximal stress level of ±180 MPa in the welded joint.

  2. The influence of specimen size on creep crack growth rate in cross-weld CT specimens cut out from a welded component

    International Nuclear Information System (INIS)

    Andersson, Peder; Segle, Peter; Samuelson, Lars Aa.

    1999-04-01

    A 3D finite element study of creep crack growth in cross-weld CT specimens with material properties of 2.25Cr1Mo at 550 deg C is carried out, where large strain and displacement theory is used. The creep crack growth rate is calculated using a creep ductility based damage model, in which the creep strain rate perpendicular to the crack plane ahead of the crack tip is integrated, considering the multiaxial stress state. The influence of specimen size on creep crack growth rate under constant load is given special attention, but the possibility to transfer results from cross-weld CT specimens to welded high temperature components is also investigated. The creep crack growth rate of a crack in a circumferentially welded pipe is compared with the creep crack growth rate of cross-weld CT specimens of three different sizes, cut out from the pipe. Although the constraint ahead of the crack tip is higher for a larger CT specimen, the creep crack growth rate is higher for a smaller specimen than for a larger one if they are loaded to attain the same stress intensity factor. If the specimens are loaded to the same C* value, however, a more complicated pattern occurs; depending on the material properties of the weldment constituents, the CT specimen with the intermediate size will either yield the highest or the lowest creep crack growth rate

  3. Mismatch effect on CT specimen mechanical effect and consequences on the weld toughness characterization

    International Nuclear Information System (INIS)

    Marie, S.; Nedelec, M.

    2012-01-01

    The welded joints are particularly sensitive areas in the structures in terms of harmfulness of defects. Given the complexity of the problem (geometry poorly controlled, multi-material aspect, the potential influence of residual stresses), the tests are conducted based on pessimistic assumptions that can wrap all the uncertainties of the problem. In the case of a defect assessment, the considered toughness is deduced from conventional characterization tests with a crack in the welding, considering the current standards, ISO 12135 or ASTM E-1820 which are valid only for an homogeneous specimen. In 2010, a new standard ISO 16563 was published to address the specificity of welded joints. If it covers some of the difficulties, it remains incomplete. In nuclear piping, welds have a mismatch M, i.e. the ratio between the yield strength of the weld metal and the base metal, usually greater than 1: this avoids any problem of strain localization at the junction and ensure that the stresses in the base metal are also easily supported by the welded joint. In this configuration, it turns out that for a given mechanical loading, a crack in the weld located generally has a solicitation, quantified by the parameter J, less (depending on the size of the junction) to those that would see the same crack located in the base metal. Unfortunately, this phenomenon exists also potentially for a characterization test, which would overestimate the true toughness of the welded joint. Plasticity that develops from the crack tip can quickly reach this interface and be affected. To evaluate this phenomenon, we considered two types of representative welded joint (PWR secondary loop ferritic weld and a 316 stainless steel weld) and performed a F.E. analysis of the multi-material CT specimen mechanical answer and on the η coefficient conventionally used to derive the plastic component of J from the area under the curve force-opening displacement. (authors)

  4. Stable crack growth behaviors in welded CT specimens -- finite element analyses and simplified assessments

    International Nuclear Information System (INIS)

    Yagawa, Genki; Yoshimura, Shinobu; Aoki, Shigeru; Kikuchi, Masanori; Arai, Yoshio; Kashima, Koichi; Watanabe, Takayuki; Shimakawa, Takashi

    1993-01-01

    The paper describes stable crack growth behaviors in welded CT specimens made of nuclear pressure vessel A533B class 1 steel, in which initial cracks are placed to be normal to fusion line. At first, using the relations between the load-line displacement (δ) and the crack extension amount (Δa) measured in experiments, the generation phase finite element crack growth analyses are performed, calculating the applied load (P) and various kinds of J-integrals. Next, the simplified crack growth analyses based on the GE/EPRI method and the reference stress method are performed using the same experimental results. Some modification procedures of the two simplified assessment schemes are discussed to make them applicable to inhomogeneous materials. Finally, a neural network approach is proposed to optimize the above modification procedures. 20 refs., 13 figs., 1 tab

  5. Design of specimen for weld residual stress simulation

    International Nuclear Information System (INIS)

    Kim, Jin Weon; Park, Jong Sun; Lee, Kyung Soo

    2008-01-01

    The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding of pipe. Specimen type and method for residual stress generation were proposed based on the review of prior studies and parametric finite element simulation. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element simulation considered in the specimen design. Comparison of residual strains measured at several locations of specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen can reasonably simulate the residual stress of circumferential butt welding of pipe

  6. Strip specimen tests for pipeline materials and girth welds

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, William C. [Edison Welding Institute (EWI), Columbus, Ohio (United States)

    2009-07-01

    Strip specimen testing of pipeline materials has been widely applied as a method of getting data relevant to the performance of pipelines under axial direction loading. Comparisons of strip specimen against smaller standard tests (round tensile bar, fracture toughness specimens, polished round bars) and against full-scale or large-scale testing will be explored. Data from early-generation pipe welds from the 1920's to the 1940's to the most recent materials for offshore reeled pipe will be used for examples. Strip samples can provide full thickness information to take account of varying material properties or imperfection distribution through the thickness. Strip samples can also accommodate measurement of effects of the original surface finish or weld surface shape. Strip samples have more design flexibility than standard tests, but must be designed to limit stress concentrations and effects of local bending. (author)

  7. Fracture resistance of welded panel specimen with perpendicular crack in tensile

    International Nuclear Information System (INIS)

    Gochev, Todor; Adziev, Todor

    1998-01-01

    Defects caused by natural crack in welded joints of high-strength low-alloy (HSLA) steels are very often. Perpendicular crack in welded joints and its heat treatment after the welding has also an influence on the fracture resistance. The fracture resistance of welded joints by crack in tense panel specimens was investigated by crack mouse opening displesment (CMOD), the parameter of fracture mechanic. Crack propagation was analysed by using a metallographic analysis of fractured specimens after the test. (Author)

  8. Laser weld reconstitution of conventional Charpy and Miniaturized Notch Test (MNT) specimens

    International Nuclear Information System (INIS)

    Manahan, M.P.; Williams, J.; Martukanitz, R.P.

    1993-01-01

    As nuclear power plants approach end-of-license (EOL) and consideration is given to license renewal, there is an ever increasing need to expand the amount of data obtainable from the original surveillance specimens. A laser welding technique to reconstitute broken Charpy specimens is being developed to produce both conventional and miniaturized Charpy specimens. This paper reports on early laser welding development efforts and summarizes previous proof-of-principle experiments on a 1/16 scale miniaturized Charpy test. In order to benchmark the laser welding procedure, the laser-reconstituted specimen data have been compared with the original specimen data. In addition, the microstructure after welding has been examined to ensure that the material in the vicinity of the notch is essentially unchanged after the welding process. Data which characterize the thermal transient during welding are obtained by attaching thermocouples to the specimens. Other important considerations include perturbation of the stress field near the notch, dynamic stress waves, and contact of the weld region with the tup. Precise control of welding parameters has been demonstrated, heat-affected zones as small as 0.25 mm can be achieved, and sufficient penetration depth can be obtained to enable welding thick sections (1T or greater) to yield conventional Charpy specimens or fracture toughness specimens and thin sections (∼5 mm) to yield Miniaturized Notch Test (MNT) specimens

  9. Experimental investigation of the thickness effect for large as-welded SAW S355 steel specimens

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús; Jensen, Jørgen Juncher; Berggreen, Christian

    2016-01-01

    The presented work aims to investigate and establish a pre-cise, thorough and detailed database from series of experi-mental testing of submerged arc welded (SAW) specimens of various thicknesses typically applied in ships and offshore structures and foundations. Welded structures of all sizes...... and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has therefore received much attention from universities, re-search institutions along with industry as it is of significant...

  10. Numerical Analysis of Crack Progress in Different Areas of a Friction Stir Welded Bead for an 5251 H14 Aluminum Alloy Specimen

    Directory of Open Access Journals (Sweden)

    Y. Kambouz

    2014-02-01

    Full Text Available The assemblies welded by Friction Stir Welding have a major advantage which is the absence of a metal filler. This process contributes to the welding of materials that are known to be difficult to weld using the conventional techniques often employed in the field of transport, for example in the automobile body by applying a spot welding. The numerical modeling of this type of process is complex, not only in terms of the variety of physical phenomena which must be considered, but also because of the experimental procedure that must be followed in order to verify and validate numerical predictions. In this work, a finite element model is proposed in order to simulate the crack propagation under monotonic loading in different areas of the weld seam of a strain hardening CT-50 aluminum alloy 5251H14 specimen.

  11. Prediction of retained residual stresses in laboratory fracture mechanics specimens extracted from welded components

    International Nuclear Information System (INIS)

    Hurlston, R.G.; Sherry, A.H.; James, P.; Sharples, J.K.

    2015-01-01

    The measurement of weld material fracture toughness properties is important for the structural integrity assessment of engineering components. However, welds can contain high levels of residual stress and these can be retained in fracture mechanics specimens, particularly when machined from non-stress relieved welds. Retained residual stresses can make the measurement of valid fracture toughness properties difficult. This paper describes the results of analytical work undertaken to investigate factors that can influence the magnitude and distribution of residual stresses retained in fracture mechanics specimen blanks extracted from as-welded ferritic and austenitic stainless steel plates. The results indicate that significant levels of residual stress can be retained in specimen blanks prior to notching, and that the magnitude and distribution of stress is dependent upon material properties, specimen geometry and size, and extraction location through the thickness of the weld. Finite element modelling is shown to provide a useful approach for estimating the level and distributions of retained residual stresses. A new stress partitioning approach has been developed to estimate retained stress levels and results compare favourably with FE analysis and available experimental data. The approach can help guide the selection of specimen geometry and machining strategies to minimise the level of residual stresses retained in fracture mechanics specimen blanks extracted from non stress-relieved welds and thus improve the measurement of weld fracture toughness properties. - Highlights: • A simplified method for generating realistic weld residual stresses has been developed. • It has been shown that significant levels of residual stress can be retained within laboratory fracture mechanics specimens. • The level and distribution is dependant upon material, specimen type, specimen size and extraction location. • A method has been developed to allow estimates of the

  12. Development of resistance welding process. 4. Preparation of pressuring enclosed creep test specimen of 7A material

    International Nuclear Information System (INIS)

    Endo, Hideo; Seki, Masayuki; Ishibashi, Fujio; Hirako, Kazuhito; Tsukada, Tatsuya

    2001-02-01

    Mechanical strength in the position welded by resistance welding system was examined in 1999. The test specimens were destroyed in the welding position in a shorter time than expected in the creep test. Therefore, test specimens were prepared to evaluate the cause of destruction. Inner-pressure enclosed creep test specimens were prepared by resistance welding method. Cladding material with low deviation of thickness and high re-crystallization rate was used. Heat treatment after resistance welding was performed to remove the influence of residual stress and the precipitation of carbides. (1) Before preparation of specimens, the welding condition was fixed. Three test specimens were prepared. Two specimens without heat treatment were transported to MMS in Oarai Engineering Center on Aug. 4, 2000. One specimen with heat treatment was transported to MMS after evaluating the residual stress to get optimum heat treatment condition. (2) Specimens were prepared with welding end plugs to both ends of ferritic ODS cladding. Enclosing sides were welded with highly strong Ferritic/Martensitic steel end plugs. The other sides were welded with ferritic ODS end plugs. (3) Some kinds of electrical wave data were obtained during performing welding. Welding position was evaluated with supersonic detector after performing welding. (4) Mechanical strength of welding position in high temperature 800degC was confirmed to be equal to or larger than that of cladding material. The highly qualified specimens in the present were successfully prepared. (author)

  13. 3D analyses of the effect of weld orientation in Charpy specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2004-01-01

    . The onset of cleavage is taken to occur when the average of the maximum principal stress over a specified volume attains a critical value. The weld analyzed here is overmatched, so that the yield strength for the weld is larger than that of the base material. Analyses are carried out for specimens where...... the notch is cut parallel to the surface of the test piece, as well as more complex geometries where the notched surface of the specimen is rotated relative to the surface of the test piece. It is found that even for a homogeneous material the brittle-ductile transition can be much affected by three...... dimensional effects; for example, curvature of the deformed free surface gives rise to a stress increase that promotes cleavage. Furthermore, for the rotated specimens the weld geometry relative to the notched specimen surface is so complex that only a full 3D analysis is able to account for the interaction...

  14. Measurement of deformation field in CT specimen using laser speckle

    International Nuclear Information System (INIS)

    Jeon, Moon Chang; Kang, Ki Ju

    2001-01-01

    To obtain A 2 experimentally in the J-A 2 theory, deformation field on the lateral surface of a CT specimen was to be determined using laser speckle method. The crack growth was measured using direct current potential drop method and most procedure of experimental and data reduction was performed according to ASTM Standard E1737-96. Laser speckle images during crack propagation were monitored by two CCD cameras to cancel the effect of rotation and translation of the specimen. An algorithm to pursue displacement of a point from each image was developed and successfully used to measure A 2 continuously as the crack tip was propagated. The effects of specimen thickness on J-R curve and A 2 were explored

  15. JR-curves of wide plates and CT25 specimens

    International Nuclear Information System (INIS)

    Aurich, D.; Wobst, K.; Krafka, H.

    1987-01-01

    In connection with the problem of the applicability of the characteristic specimen date - i.e. the initiation and stable crack propagation under maximal loads, together with the elastic-plastic material behaviour - to that of actual components, spot-check type beside tests were conducted using wide-plate central crack, central notch (CCT, CNT) and double external crack (DECT) samples. The material in question was an StE 460 steel. A comparison between the determined values shows that the assessed pressure vessel behaviour differs extensively to the values derived from the CCT and CNT specimens. The corresponding results obtained from the CT25 and DECT specimens vary only slightly in the region of interest and correspond to real vessel values. (orig./DG) [de

  16. Weld investigations by 3D analyses of Charpy V-notch specimens

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Allan

    2005-01-01

    The Charpy impact test is a standard procedure for determining the ductile-brittle transition in welds. The predictions of such tests have been investigated by full three dimensional transient analyses of Charpy V-notch specimens. The material response is characterised by an elastic...... parameters in the weld material differ from those in the base material, and the heat a®ected zone (HAZ) tends to be more brittle than the other material regions. The effect of weld strength undermatch or overmatch is an important issue. Some specimens, for which the notched surface is rotated relative...... to the surface of the test piece, have so complex geometry that only a full 3D analysis is able to account for the interaction of failure in the three different material regions, whereas ther specimens can be approximated in terms of a planar analysis....

  17. Stress corrosion cracking tests on electron beam welded carbon steel specimens in carbonate-bicarbonate solution

    International Nuclear Information System (INIS)

    Parkins, R.N.

    1985-04-01

    Stress corrosion cracking tests have been performed on tapered carbon steel test pieces containing electron beam welds with a view to defining susceptibility to such cracking in a carbonate-bicarbonate solution at 90 C and an appropriate electrode potential. The tests involved applying cyclic loads to the specimens and it is shown that the threshold stress for cracking reduces linearly with increase in the magnitude of the cyclic load component. Extrapolation of these trends to zero fluctuating stress indicates static load threshold stresses in the vicinity of the yield stress (i.e. about 300 N/mm 2 for parent plate without a weld, 400 N/mm 2 for specimens with welds on one side only and 600 N/mm 2 for specimens having welds penetrating through the thickness of the specimen). The averages of the maximum crack velocities observed were least for parent plate material and greatest for weld metal, the former being essentially intergranular in morphology and the latter mostly transgranular, with heat affected zone material being intermediate between these extremes. (author)

  18. Crack growth modeling in a specimen with polymer weld

    Czech Academy of Sciences Publication Activity Database

    Ševčík, Martin; Hutař, Pavel; Náhlík, Luboš; Lach, R.; Knésl, Zdeněk; Grellmann, W.

    488-489, č. 1 (2012), s. 158-161 ISSN 1013-9826. [International Conference on Fracture and Damage Mechanics - FDM 2011 /10./. Dubrovník, 19.09.2011-21.09.2011] R&D Projects: GA ČR GC101/09/J027; GA ČR GD106/09/H035 Institutional research plan: CEZ:AV0Z20410507 Keywords : polymer weld * crack propagation * graded structure * fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics

  19. Proton irradiation effects on tensile and bend-fatigue properties of welded F82H specimens

    Energy Technology Data Exchange (ETDEWEB)

    Saito, S., E-mail: saito.shigeru@jaea.go.j [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Kikuchi, K.; Hamaguchi, D. [JAEA Tokai, J-PARC Center, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Usami, K.; Ishikawa, A.; Nishino, Y.; Endo, S. [JAEA Tokai, Department of Hot Laboratories, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kawai, M. [KEK, Tsukuba-shi, Ibaraki-ken 305-0801 (Japan); Dai, Y. [PSI, Spallation Source Division, 5232 Villigen PSI (Switzerland)

    2010-03-15

    In several institutes, research and development for an accelerator-driven transmutation system (ADS) have been progressed. Ferritic/martensitic (FM) steels are the candidate materials for the beam window of ADS. To evaluate of the mechanical properties of the irradiated materials, the post irradiation examination (PIE) work of the SINQ (Swiss spallation neutron source) target irradiation program (STIP) specimens was carried out at JAEA. In present study, the results of PIE on FM steel F82H and its welded joint have been reported. The present irradiation conditions of the specimens were as follows: proton energy was 580 MeV. Irradiation temperatures were ranged from 130 to 380 deg. C, and displacement damage level was ranged from 5.7 to 11.8 dpa. The results of tensile tests performed at 22 deg. C indicated that the irradiation hardening occurred with increasing the displacement damage up to 10.1 dpa at 320 deg. C irradiation. At higher dose (11.8 dpa) and higher temperature (380 deg. C), irradiation hardening was observed, but degradation of ductility was relaxed in F82H welded joint. In present study, all specimens kept its ductility after irradiation and fractured in ductile manner. The results on bend-fatigue tests showed that the fatigue life (N{sub f}) of F82H base metal irradiated up to 6.3 dpa was almost the same with that of unirradiated specimens. The N{sub f} of the specimens irradiated up to 9.1 dpa was smaller than that of unirradiated specimens. Though the number of specimen was limited, the N{sub f} of F82H EB (15 mm) and EB (3.3 mm) welded joints seemed to increase after irradiation and the fracture surfaces of the specimens showed transgranular morphology. While F82H TIG welded specimens were not fractured by 10{sup 7} cycles.

  20. Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

    2016-05-15

    This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

  1. Influence of heat treatments for laser welded semi solid metal cast A356 alloy on the fracture mode of tensile specimens

    CSIR Research Space (South Africa)

    Kunene, G

    2008-09-01

    Full Text Available were then butt laser welded. It was found that the pre-weld as cast, T4 and post-weld T4 heat treated specimens fractured in the base metal. However, the pre-weld T6 heat treated specimens were found to have fractured in the heat affected zone (HAZ)...

  2. J-integral analysis of heterogeneous mismatched girth welds in clamped single-edge notched tension specimens

    International Nuclear Information System (INIS)

    Hertelé, Stijn; De Waele, Wim; Verstraete, Matthias; Denys, Rudi; O'Dowd, Noel

    2014-01-01

    Flaw assessment procedures require a quantification of crack driving force, and such procedures are generally based on the assumption of weld homogeneity. However, welds generally have a heterogeneous microstructure, which will influence the crack driving force. This paper describes a stress-based methodology to assess complex heterogeneous welds using a J-based approach. Clamped single-edge notched tension specimens, representative of girth weld flaws, are analyzed and the influence of weld heterogeneity on crack driving force has been determined. The use of a modified limit load for heterogeneous welds is proposed, suitable for implementation in a ‘homogenized’ J-integral estimation scheme. It follows from an explicit modification of an existing solution for centre cracked tension specimens. The proposed solution provides a good estimate of crack driving force and any errors in the approximation may be accounted for by means of a small safety factor on load bearing capacity. - Highlights: • We present a crack driving force estimation procedure for heterogeneous welds. • The procedure is based on a ‘homogenized’ version of the EPRI equation. • Complex welds are translated into equivalent idealized mismatched welds. • The procedure is validated for clamped SE(T) specimens. • A mismatch limit load for clamped SE(T) specimens is developed

  3. FRACTURE MECHANICS APPROACH TO ESTIMATE FATIGUE LIVES OF WELDED LAP-SHEAR SPECIMENS

    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.; Michigan, J.

    2014-04-25

    A full range of stress intensity factor solutions for a kinked crack is developed as a function of weld width and the sheet thickness. When used with the associated main crack solutions (global stress intensity factors) in terms of the applied load and specimen geometry, the fatigue lives can be estimated for the laser-welded lap-shear specimens. The estimations are in good agreement with the experimental data. A classical solution for an infinitesimal kink is also employed in the approach. However, the life predictions tend to overestimate the actual fatigue lives. The traditional life estimations with the structural stress along with the experimental stress-fatigue life data (S-N curve) are also provided. In this case, the estimations only agree with the experimental data under higher load conditions.

  4. Evaluation of local deformation behavior accompanying fatigue damage in F82H welded joint specimens by using digital image correlation

    International Nuclear Information System (INIS)

    Nakata, Toshiya; Tanigawa, Hiroyasu

    2012-01-01

    Highlights: ► In tensile, the TIG welded joint material was concentrated in the THAZ. ► In tensile, fracture occurred at the point where the axial strain converged. ► In fatigue, fracture occurred at the point where the Max. shear strain converged. ► Many macrocracks and cavities formed in the FGHAZ and THAZ of the cross section. - Abstract: By using digital image correlation, the deformation behaviors of local domains of F82H joint specimens welded using tungsten inert gas (TIG) and electron beam (EB) welding were evaluated during tensile and fatigue testing. In the tensile test specimens, the tensile strength decreased in the TIG-welded joints, and ductility decreased in both the EB- and TIG-welded joints. Because axial strain increased in the tempered heat-affected zone (HAZ) and led to the fracture of the TIG-welded joint, the strength was considered to have decreased because of welding. In fatigue testing, the number of cycles to fracture for the welded joint decreased to less than 40–60% of that for the base metal. For both fracture specimens, the largest value of shear strain was observed in the region approximately between the fine-grained HAZ and tempered HAZ; this shear strain ultimately led to fracture. Cavities and macrocracks were observed in the fine-grained HAZ and tempered HAZ in the cross sections of the fracture specimens, and geometrical damage possibly resulted in the reduction of fatigue lifetime.

  5. 3D modelling of plug failure in resistance spot welded shear-lab specimens (DP600-steel)

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2008-01-01

    are based on uni-axial tensile testing of the basis material, while the modelled tensile response of the shear-lab specimens is compared to experimental results for the case of a ductile failure near the heat affected zone (HAZ). A parametric study for a range of weld diameters is carried out, which makes......Ductile plug failure of resistance spot welded shear-lab specimens is studied by full 3D finite element analysis, using an elastic-viscoplastic constitutive relation that accounts for nucleation and growth of microvoids to coalescence (The Gurson model). Tensile properties and damage parameters...... it possible to numerically relate the weld diameter to the tensile shear force (TSF) and the associated displacement, u (TSF) , respectively. Main focus in the paper is on modelling the localization of plastic flow and the corresponding damage development in the vicinity of the spot weld, near the HAZ...

  6. Comparison of measurement results between cervical pedicle specimens and CT images

    International Nuclear Information System (INIS)

    Zhang Guangjian; Li Hua; Liu Haiyan; Gao Zhenping

    2011-01-01

    Objective: To compare the difference between the measurement results of the cervical pedicle specimens and CT image, and provide the basis for clinical cervical screw internal fixation operation. Methods: Twenty-seven Chinese adult cadaver cervical specimens including C3 to C7 vertebrae were measured by a digital calipers and CT image, containing pedicle height (PH, PH'), pedicle width(PW, PW'), total pedicle length (TL, TL') and two pedicle lengths(PL1, PL2; PL1', PL2'). The results of specimens and CT image were compared. Results: Different cervical vertebra in the same side of specimens or CT images, PW (PW'): C3, C4< C5, C6 (P<0.05), C5, C6< C7 (P<0.01); PH (PH'): there were no significant differences; TL, PL1, PL2 (TL', PL1', PL2'): there were no marked differences. In the same cervical vertebra of the specimens or CT images, PW (PW')< PH (PH') (P<0.01), PL1 (PL1') < PL2 (PL2') (P<0.01). Conclusion: The results of measurement by CT images are not markedly different from that of specimens. CT image measurement is available before cervical screw internal fixation operation. (authors)

  7. Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

    Directory of Open Access Journals (Sweden)

    Chunlei Fan

    2018-01-01

    Full Text Available The tests of bullet impact on the base material (BM of a simple specimen with a single resistance-spot-welded (RSW nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM and the scanning electro microscope (SEM. For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling. For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the “notch tip” spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the “notch tip”, propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle

  8. Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

    Science.gov (United States)

    Fan, Chunlei; Ma, Bohan; Chen, Danian; Wang, Huanran; Ma, Dongfang

    2018-01-01

    The tests of bullet impact on the base material (BM) of a simple specimen with a single resistance-spot-welded (RSW) nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR) is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM) and the scanning electro microscope (SEM). For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling). For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the "notch tip" spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the "notch tip", propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle fracture and ductile

  9. In-line phase contrast micro-CT reconstruction for biomedical specimens.

    Science.gov (United States)

    Fu, Jian; Tan, Renbo

    2014-01-01

    X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

  10. Evaluation on ductile tearing properties of girth weld pipelines using SE(T) and SE(B) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, Leonardo Luiz Siqueira; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Naval e Oceanica

    2012-07-01

    Predictive methodologies aimed at quantifying the impact of defects in oil and gas pipelines play a key role in safety assessment procedures of in-service facilities. Current methodologies for structural integrity assessments advocate the use of geometry dependent resistance curves so that crack-tip constraint in the test specimen closely matches the crack tip constraint for the structural component. Testing standards now under development to measure fracture resistance of pipeline steels (J and CTOD) most often employ single edge notched specimens under tension (SENT) to match a postulated defect in the structural component. This paper presents an investigation of the ductile tearing properties for a girth weld of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-R curves). Testing of the girth weld pipeline steels employed side-grooved, clamped SE(T) specimen with center-crack weld and side-grooved, three-point bending SE(B) (or SENB) specimens to determine the J-R curves. The methods were compared in terms of geometry, relative crack size and crack-tip constraint, and the results were applied to a case study, to evaluate the degree of conservativeness in defect acceptance criteria. The tests involving SE(B) specimens are usually considered conservative, however, the comparison between this two methods may point an accurate alternative for girth weld assessments, since adequate geometry is adopted to describe accurately the structure's behavior. (author)

  11. Application of the standard options of the FITNET procedure to the structural integrity assessment of welded specimens containing cracks

    International Nuclear Information System (INIS)

    Dzioba, Ihor; Neimitz, Andrzej

    2007-01-01

    In this paper, the structural integrity of welded specimens is assessed. The specimens were welded using a conventional technique, MAG, and an unconventional one, laser technology. Welded specimens were of the central crack under tension (CCT) type. The elements were loaded, the maximum load was recorded, and the second and the third options of the FITNET procedure were utilized to estimate the critical loading. Estimated and recorded loads were compared to verify the conservatism of the estimated results. For comparison, the results obtained using Option 1 of the FITNET procedure (not recommended in the case analysed) are also presented. Results of the mechanical properties, hardness, fracture toughness for the base and the weld material and residual stress distributions are reported for both MAG and laser welding techniques. The results obtained confirm that the FITNET procedures were properly deigned. The higher the level of analysis, the smaller the conservatism of predictions observed. The overconservative conclusions, following from the lower level of analysis, suggest that the structural element is endangered, do not have to exclude it from exploitation. The higher level of analysis can, in some cases, confirm that the structural element containing a crack can still be exploited

  12. Influence of heat input on weld bead geometry using duplex stainless steel wire electrode on low alloy steel specimens

    Directory of Open Access Journals (Sweden)

    Ajit Mondal

    2016-12-01

    Full Text Available Gas metal arc welding cladding becomes a popular surfacing technique in many modern industries as it enhances effectively corrosion resistance property and wear resistance property of structural members. Quality of weld cladding may be enhanced by controlling process parameters. If bead formation is found acceptable, cladding is also expected to be good. Weld bead characteristics are often assessed by bead geometry, and it is mainly influenced by heat input. In this paper, duplex stainless steel E2209 T01 is deposited on E250 low alloy steel specimens with 100% CO2 gas as shielding medium with different heats. Weld bead width, height of reinforcement and depth of penetration are measured. Regression analysis is done on the basis of experimental data. Results reveal that within the range of bead-on-plate welding experiments done, parameters of welding geometry are on the whole linearly related with heat input. A condition corresponding to 0.744 kJ/mm heat input is recommended to be used for weld cladding in practice.

  13. Dual-Energy CT of Rectal Cancer Specimens

    DEFF Research Database (Denmark)

    Al-Najami, Issam; Beets-Tan, Regina G H; Madsen, Gunvor

    2016-01-01

    is represented by a certain effective Z value, which allows for information on its composition. OBJECTIVE: We wanted to standardize a method for dual-energy scanning of rectal specimens to evaluate the sensitivity and specificity of benign versus malignant lymph node differentiation. Histopathological evaluation...... cancer. MAIN OUTCOME MEASURES: We measured accuracy of differentiating benign from malignant lymph nodes by investigating the following: 1) gadolinium, iodine, and water concentrations in lymph nodes; 2) dual-energy ratio; 3) dual-energy index; and 4) effective Z value. RESULTS: Optimal discriminations...... between benign and malignant lymph nodes were obtained using the following cutoff values: 1) effective Z at 7.58 (sensitivity, 100%; specificity, 90%; and accuracy, 93%), 2) dual-energy ratio at 1.0 × 10 (sensitivity, 96%; specificity, 87%; and accuracy, 90%), 3) dual-energy index at 0.03 (sensitivity, 97...

  14. Multiaxial Cycle Deformation and Low-Cycle Fatigue Behavior of Mild Carbon Steel and Related Welded-Metal Specimen

    Directory of Open Access Journals (Sweden)

    Weilian Qu

    2017-01-01

    Full Text Available The low-cycle fatigue experiments of mild carbon Q235B steel and its related welded-metal specimens are performed under uniaxial, in-phase, and 90° out-of-phase loading conditions. Significant additional cyclic hardening for 90° out-of-phase loading conditions is observed for both base metal and its related weldment. Besides, welding process produces extra additional hardening under the same loading conditions compared with the base metal. Multiaxial low-cycle fatigue strength under 90° out-of-phase loading conditions is significantly reduced for both base-metal and welded-metal specimens. The weldment has lower fatigue life than the base metal under the given loading conditions, and the fatigue life reduction of weldment increases with the increasing strain amplitude. The KBM, FS, and MKBM critical plane parameters are evaluated for the fatigue data obtained. The FS and MKBM parameters are found to show better correlation with fatigue lives for both base-metal and welded-metal specimens.

  15. An Inset CT Specimen for Evaluating Fracture in Small Samples of Material

    Science.gov (United States)

    Yahyazadehfar, M.; Nazari, A.; Kruzic, J.J.; Quinn, G.D.; Arola, D.

    2013-01-01

    In evaluations on the fracture behavior of hard tissues and many biomaterials, the volume of material available to study is not always sufficient to apply a standard method of practice. In the present study an inset Compact Tension (inset CT) specimen is described, which uses a small cube of material (approximately 2×2×2 mm3) that is molded within a secondary material to form the compact tension geometry. A generalized equation describing the Mode I stress intensity was developed for the specimen using the solutions from a finite element model that was defined over permissible crack lengths, variations in specimen geometry, and a range in elastic properties of the inset and mold materials. A validation of the generalized equation was performed using estimates for the fracture toughness of a commercial dental composite via the “inset CT” specimen and the standard geometry defined by ASTM E399. Results showed that the average fracture toughness obtained from the new specimen (1.23 ± 0.02 MPa•m0.5) was within 2% of that from the standard. Applications of the inset CT specimen are presented for experimental evaluations on the crack growth resistance of dental enamel and root dentin, including their fracture resistance curves. Potential errors in adopting this specimen are then discussed, including the effects of debonding between the inset and molding material on the estimated stress intensity distribution. Results of the investigation show that the inset CT specimen offers a viable approach for studying the fracture behavior of small volumes of structural materials. PMID:24268892

  16. Technique for the residual life assessment of high temperature components based on creep-rupture testing on welded miniature specimens

    Energy Technology Data Exchange (ETDEWEB)

    Garzillo, A.; Guardamagna, C.; Moscotti, L.; Ranzani, L. [Ente Nazionale per l`Energia Elettrica, Milan (Italy)

    1995-06-01

    Following the present trend in the development of advanced methodologies for residual life assessment of high temperature components operating in power plants, particularly in non destructive methods, a testing technique has been set up at ENEL-CRAM based on creep-rupture testa in an argon on welded miniature specimens. Five experimental systems for creep-rupture tests in an argon atmosphere have been set up which include high accuracy systems, vacuum chambers and exrwnsometer devices. With the aim of establishing and validating the suitability of the experimental methodology, creep-rupture and interrupted creep testing programmes have been performed on miniature specimens (2 mm diameter and 10 mm gauge lenght). On the basis of experience gathered by various European research laboratories, a miniature specimen construction procedure has been developed using a laser welding technique for joining threaded heads to sample material. Low alloy ferritic steels, such as virgin 2.25CrlMo, 0.5Cr 0.5Mo 0.25V, and IN 738 superalloy miniature specimens have been investigated and the results, compared with those from standard specimens, show a regular trend in deformation vs time. Additional efforts to provide guidelines for material sampling from each plant component will be required in order to reduce uncertainties in residual life prediction.

  17. Specimen Test of Large-Heat-Input Fusion Welding Method for Use of SM570TMCP

    Directory of Open Access Journals (Sweden)

    Dongkyu Lee

    2015-01-01

    Full Text Available In this research, the large-heat-input welding conditions optimized to use the rear plate and the high-performance steel of SM570TMCP, a new kind of steel suitable for the requirements of prospective customers, are proposed. The goal of this research is to contribute to securing the welding fabrication optimized to use the high-strength steel and rear steel plates in the field of construction industry in the future. This research is judged to contribute to securing the welding fabrication optimized to use the high-strength steel and rear steel plates in the field of construction industry in the future.

  18. Studies on diagnostic value of CT images for hypopharyngeal cancer by comparing with sliced specimens

    International Nuclear Information System (INIS)

    Fujimura, Akiko

    1988-01-01

    The findings of preoperative CT were compared with extirpated specimens in 11 patients to evaluate the value of CT in diagnosing the extent of hypopharyngeal cancer. CT was capable of detecting tumor extent to the submucosal fibrofatty tissue, except for the case of tumor extent to the laryngeal ventricle that contains many mucous glands and is usually depicted as a dense shadow. When the margin of ossified cortex of the thyroid cartilage was irregular and surrounded by tumor shadow, or when the margin of the cricoid cartilage was irregular and accompanied by increased medullary concentration, the invasion of the tumor into these cartilages was histopathologically demonstrated. Tumor extension next to these ossified cartilages did not indicate histopathological invasion of the tumor whenever their margins were smooth and regular. The intrinsic laryngeal muscle and the inferior pharyngeal constrictor muscle were identified on CT. Tumor extent to these muscles was well correlated to histologically demonstrated tumor invasion. When vocal cord fixation was present, CT showed tumor extent either to the paralaryngeal space only or to the paralaryngeal space and thyroarytenoid muscle or posterior cricoarytenoid muscle. Extraluminal spread through the thyrohyoid membrane was depicted on CT as a distinctive shadow in the visceral space that surrounds the hypopharyngeal cavity. Computed tomography overestimated tumor invation into the submucosal layer, muscles, or laryngeal cartilages. (Namekawa, K.)

  19. Measurement and prediction of residual stress in a bead-on-plate weld benchmark specimen

    International Nuclear Information System (INIS)

    Ficquet, X.; Smith, D.J.; Truman, C.E.; Kingston, E.J.; Dennis, R.J.

    2009-01-01

    This paper presents measurements and predictions of the residual stresses generated by laying a single weld bead on a flat, austenitic stainless steel plate. The residual stress field that is created is strongly three-dimensional and is considered representative of that found in a repair weld. Through-thickness measurements are made using the deep hole drilling technique, and near-surface measurements are made using incremental centre hole drilling. Measurements are compared to predictions at the same locations made using finite element analysis incorporating an advanced, non-linear kinematic hardening model. The work was conducted as part of an European round robin exercise, coordinated as part of the NeT network. Overall, there was broad agreement between measurements and predictions, but there were notable differences

  20. Automated flaw detection scheme for cast austenitic stainless steel weld specimens using Hilbert-Huang transform of ultrasonic phased array data

    International Nuclear Information System (INIS)

    Khan, Tariq; Majumdar, Shantanu; Udpa, Lalita; Ramuhalli, Pradeep; Crawford, Susan; Diaz, Aaron; Anderson, Michael T.

    2012-01-01

    The objective of this work is to develop processing algorithms to detect and localize flaws using ultrasonic phased-array data. Data was collected on cast austenitic stainless stell (CASS) weld specimens onloan from the U.S. nuclear power industry' Pressurized Walter Reactor Owners Group (PWROG) traveling specimen set. Each specimen consists of a centrifugally cast stainless stell (CCSS) pipe section welded to a statically cst(SCSS) or wrought (WRSS) section. The paper presents a novel automated flaw detection and localization scheme using low frequency ultrasonic phased array inspection singals from the weld and heat affected zone of the based materials. The major steps of the overall scheme are preprocessing and region of interest (ROI) detection followed by the Hilbert-Huang transform (HHT) of A-scans in the detected ROIs. HHT offers time-frequency-energy distribution for each ROI. The Accumulation of energy in a particular frequency band is used as a classification feature for the particular ROI

  1. Effect of reverse cyclic loading on the fracture resistance curve in C(T) specimen

    International Nuclear Information System (INIS)

    Sung Seok, C.; Jin Kim, Y.; Il Weon, J.

    1999-01-01

    Fracture resistance (J-R) curves, which are used for elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to investigate the effect of reverse cyclic loading on the J-R curves in C(T) specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance tests on C(T) specimens with varying the load ratio and the incremental plastic displacement were performed, and the test results showed that the J-R curves were decreased with decreasing the load ratio and decreasing the incremental plastic displacement. Direct current potential drop (DCPD) method was used for the detection of crack initiation and crack growth in typical laboratory J-R tests. The values of crack initiation J-integral (J I ) and crack initiation displacement (δ i ) were also obtained by using the DCPD method. (orig.)

  2. Fatigue damage observed non-destructively in fibre composite coupon test specimens by X-ray CT

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Mikkelsen, Lars Pilgaard

    2016-01-01

    This study presents a method for monitoring the 3D fatigue damage progression on a micro-structural level in a glass fibre/polymer coupon test specimen by means of laboratory X-ray Computed Tomography (CT). A modified mount and holder made for the standard test samples to fit into the X-ray CT...... scanner along with a tension clamp solution is presented. Initially, the same location of the test specimen is inspected by ex-situ X-ray CT during the fatigue loading history, which shows the damage progression on a micro-structural level. The openings of individual uni-directional (UD) fibre fractures...

  3. Analysis of the truth loading conditions of a austenitic CT specimen during a SCC experiment

    International Nuclear Information System (INIS)

    Marie, S.; Guerre, C.; Herms, E.

    2012-01-01

    With the aim to investigate the influence of strain hardening on the stainless steels susceptibility to stress corrosion cracking, tests were conducted in PWR environment on CT specimens, taken from a 316L stainless steel sheet cold rolled to 40% in thickness reduction. The initial cracks obtained by the fatigue pre-cracking have an atypical 'V' shape with smaller propagation in the center of the CT thickness compared to nominal propagation observed at both sides. The initial explanation was to consider a stress intensity factor derived from classical reference solution on the basis of a straight crack front, and considering the local value of the crack depth in the equation. This assumption raised several problems analyses in this paper. This particular shape of the initial defect may be related to several factors, and partly to the 40% cold rolling. It is likely that the hardening is not uniform, with a higher rate at the specimen sides than in the central area. In addition, significant residual stresses due to the gradient of mechanical properties are observed. Due to the high rate of work hardening by rolling of the sheet metal, a gradient of the mechanical properties through the thickness was determined, and the residual stresses profile induced by this process was measured. The variations obtained are consistent with each other: the material is more hardened in the vicinity of specimen surface and residual stresses are compressive in nature in the central part of the specimen and of tensile type on the flanks. All these data were firstly considered in order to assess their role regarding the particular form of the initial crack front obtained after fatigue: the 3D finite element calculations taking into account the true shape of the crack front demonstrate the relationship between the characteristics of the experimental crack front obtained after fatigue pre-cracking and the residual stresses. Moreover, from the residual stresses measured on the plate where

  4. Analysis of Deformation and Failure Behaviors of TIG Welded Dissimilar Metal Joints Using Miniature Tensile Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji-Hwan; Jahanzeb, Nabeel; Kim, Min-Seong; Hwang, Ji-Hyun; Choi, Shi-Hoon [Sunchon National University, Suncheon (Korea, Republic of)

    2017-02-15

    The deformation and failure behaviors of dissimilar metal joints between SS400 steel and STS316L steel were investigated. The dissimilar metal joints were fabricated using the tungsten inert gas (TIG) welding process with STS309 steel as a filler metal. The microstructures of the dissimilar metal joints were investigated using an optical microscope and EBSD technique. The mechanical properties of the base metal (BM), heat affected zone (HAZ) and weld metal (WM) were measured using a micro-hardness and micro-tension tester combined with the digital image correlation (DIC) technique. The HAZ of the STS316L steel exhibited the highest micro-hardness value, and yield/tensile strengths, while the BM of the SS440 steel exhibited the lowest micro-hardness value and yield /tensile strengths. The grain size refinement in the HAZ of SS400 steel induced an enhancement of micro-hardness value and yield/tensile strengths compared to the BM of the SS400 steel. The WM, which consists of primary δ-ferrite and a matrix of austenite phase, exhibited relatively a high micro-hardness value, yield /tensile strengths and elongation compared to the BM and HAZ of the SS400 steel.

  5. Micro-CTvlab: A web based virtual gallery of biological specimens using X-ray microtomography (micro-CT).

    Science.gov (United States)

    Keklikoglou, Kleoniki; Faulwetter, Sarah; Chatzinikolaou, Eva; Michalakis, Nikitas; Filiopoulou, Irene; Minadakis, Nikos; Panteri, Emmanouela; Perantinos, George; Gougousis, Alexandros; Arvanitidis, Christos

    2016-01-01

    During recent years, X-ray microtomography (micro-CT) has seen an increasing use in biological research areas, such as functional morphology, taxonomy, evolutionary biology and developmental research. Micro-CT is a technology which uses X-rays to create sub-micron resolution images of external and internal features of specimens. These images can then be rendered in a three-dimensional space and used for qualitative and quantitative 3D analyses. However, the online exploration and dissemination of micro-CT datasets are rarely made available to the public due to their large size and a lack of dedicated online platforms for the interactive manipulation of 3D data. Here, the development of a virtual micro-CT laboratory (Micro-CT vlab ) is described, which can be used by everyone who is interested in digitisation methods and biological collections and aims at making the micro-CT data exploration of natural history specimens freely available over the internet. The Micro-CT vlab offers to the user virtual image galleries of various taxa which can be displayed and downloaded through a web application. With a few clicks, accurate, detailed and three-dimensional models of species can be studied and virtually dissected without destroying the actual specimen. The data and functions of the Micro-CT vlab can be accessed either on a normal computer or through a dedicated version for mobile devices.

  6. Nordic numerical round robin for a side-grooved ct-specimen

    International Nuclear Information System (INIS)

    Talja, H.

    1989-11-01

    The reliability of fracture mechanics assessments based on finite element method calculations has to be confirmed before making safety assessments for critical components like nuclear pressure vessels. Calculations for simulation of fracture mechanics tests and numerical round robin programmes are useful methods in such verification. In this report the results of Nordic finite element round robin calculations for a side-grooved CT-specimen are presented and compared with experimental results. The round robin consisted of two parts. In the first part two-dimensional calculations assuming plane strain and plane stress behaviour were made. In the second part extensive three-dimensional calculations were performed for best-estimate analysis of the specimen behaviour. The differences between the solutions were comparatively small. Only one two-dimensional solution, where lower order finite elements were used, deviated clearly from the other ones. A good agreement was seen between two-dimensional plane strain results and experimental results. Three-dimensional calculations corresponded very accurately with each others and the experiment

  7. 3D printing from microfocus computed tomography (micro-CT) in human specimens: education and future implications.

    Science.gov (United States)

    Shelmerdine, Susan C; Simcock, Ian C; Hutchinson, John Ciaran; Aughwane, Rosalind; Melbourne, Andrew; Nikitichev, Daniil I; Ong, Ju-Ling; Borghi, Alessandro; Cole, Garrard; Kingham, Emilia; Calder, Alistair D; Capelli, Claudio; Akhtar, Aadam; Cook, Andrew C; Schievano, Silvia; David, Anna; Ourselin, Sebastian; Sebire, Neil J; Arthurs, Owen J

    2018-06-14

    Microfocus CT (micro-CT) is an imaging method that provides three-dimensional digital data sets with comparable resolution to light microscopy. Although it has traditionally been used for non-destructive testing in engineering, aerospace industries and in preclinical animal studies, new applications are rapidly becoming available in the clinical setting including post-mortem fetal imaging and pathological specimen analysis. Printing three-dimensional models from imaging data sets for educational purposes is well established in the medical literature, but typically using low resolution (0.7 mm voxel size) data acquired from CT or MR examinations. With higher resolution imaging (voxel sizes below 1 micron, printing of micro-CT imaged specimens can provide insight into craniofacial surgical applications, developmental cardiac anatomy, placental imaging, archaeological remains and high-resolution bone imaging. We conclude with other potential future usages of this emerging technique.

  8. Imaging skeletal anatomy of injured cervical spine specimens: comparison of single-slice vs multi-slice helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Obenauer, S.; Alamo, L.; Herold, T.; Funke, M.; Kopka, L.; Grabbe, E. [Department of Radiology, Georg August-University Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

    2002-08-01

    Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT. (orig.)

  9. Detection of the anatomic structure and pathology in animal lung specimens: comparison of micro CT and multi-detector row CT

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Kun Young [National Cancer Center, Goyang (Korea, Republic of); Lee, Hyun Ju; Lee, Chang Hyun; Son, Kyu Ri; Goo, Jin Mo; Im, Jung Gi [Seoul National University Hospital and the Institute of Radiation Medicine, Seoul (Korea, Republic of); Seo, Joon Beom [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2006-05-15

    We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images ({rho} < 0.01). Agreement was fair between two observers ({kappa} = 0.38, {rho} < 0.001). The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens.

  10. Detection of the anatomic structure and pathology in animal lung specimens: comparison of micro CT and multi-detector row CT

    International Nuclear Information System (INIS)

    Lim, Kun Young; Lee, Hyun Ju; Lee, Chang Hyun; Son, Kyu Ri; Goo, Jin Mo; Im, Jung Gi; Seo, Joon Beom

    2006-01-01

    We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images (ρ < 0.01). Agreement was fair between two observers (κ = 0.38, ρ < 0.001). The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens

  11. Acoustoelastic evaluation of an OCTG pipe welded casing type API 5CT N80Q; Avaliacao acustoelastica de tubo OCTG do tipo casing API 5CT N80Q com solda

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Manoel A.C.; Bittencourt, Marcelo S.Q. [nstituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Payao Filho, Joao C [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil)

    2012-07-01

    This paper presents an acoustoelastic evaluation of an OCTG API 5CT N80Q casing pipe welded by the ERW/HFIW process, which is used in oil and gas exploration and exploitation. The ultrasonic technique of acoustic birefringence was employed to evaluate the acoustoelastic behavior of the T-380 CSN steel plate used to manufacture the pipe under study, and the acoustoelastic behavior of the pipe itself before subjected to the heat treatment of quench tempering and after subjected to hot straightening. It was observed a reduction in the level of anisotropy after these two manufacturing steps, what shows the efficacy of the heat treatment of quench tempering and hot straightening. After the hot straightening step, a test specimen was extracted from the pipe containing at its center the circumferential area of inspection under evaluation, which was subjected to a milling cutting operation along the weld. The opening of specimen after cutting indicated that the residual circumferential stress in the pipe was tensile. A comparison between the acoustoelastic states of the pipe after the hot straightening and the cutting operations indicated a 63% reduction in the level of anisotropy after the latter operation. (author)

  12. Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle molding

    International Nuclear Information System (INIS)

    Wang, Guilong; Zhao, Guoqun; Wang, Xiaoxin

    2013-01-01

    Highlights: ► Higher cavity surface temperature reduces tensile strength of non-weldline part. ► Higher cavity surface temperature increases weldline tensile strength for PS and PP. ► Higher cavity surface temperature reduces weldline tensile strength for ABS, ABS/PMMA, ABS/PMMA/nano-C a CO 3 and FRPP. ► Tensile strength is reduced more by the weldline than impact strength. ► FRPP has the lowest weld line factor than other plastics without reinforced fibers. - Abstract: Rapid heat cycle molding (RHCM) is a recently developed injection molding technology to enhance surface esthetic of the parts. By rapid heating and cooling of mold cavity surfaces in molding process, it can greatly alleviate or even eliminate the surface defects such as flow mark, weld line, glass fiber rich surface, silver mark, jetting mark, and swirl mark, and also improve gloss finish and dimensional accuracy without prolonging the molding cycle. Besides surface esthetic, mechanical property is also a very import issue for the molded plastic part. The aim of this study is focusing on the effects of the cavity surface temperature just before filling, T cs , in RHCM on the mechanical strength of the specimen with and without weld line. Six kinds of typical plastics including polystyrene (PS), polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene/polymethylmethacrylate (ABS/PMMA), ABS/PMMA/nano-C a CO 3 and glass fiber reinforced polypropylene (FRPP) are used in experiments. The specimens with and without a weld line are produced with the different T cs on the developed electric-heating RHCM system. Tensile tests and notched Izod impact tests are conducted to characterize the mechanical strength of the specimens molded with different cavity surface temperatures. Simulations, differential scanning calorimetry (DSC), scanning electron microscope (SEM) and optical microscope are implemented to explain the impact mechanism of T cs on mechanical properties

  13. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

    The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

  14. Aspects related to fracture toughness of mismatch welds

    International Nuclear Information System (INIS)

    Kumar, Suranjit; Khan, I.A.; Bhasin, V.; Vaze, K.K.

    2011-01-01

    In this work effect of weld strength mismatch and weld slenderness on plastic η factor was systematically examined. Solutions presented here are based on extensive two-dimensional finite element analysis. Results of FE analysis has shown that for homogeneous specimens plastic η -factor does not vary significantly with material strain hardening index. Plastic η -factors for non-hardening material models were in better agreement with ASTM solutions than for hardening material models. For mismatch welded specimens analyses were performed on Compact tension (CT) and three points bend (TPB) specimens. Studies were performed for both hardening as well as elastic-perfectly plastic (non-hardening) material models. Results of finite element analysis have shown that unlike homogeneous specimens there is an influence of material strain hardening on plastic η -factor. For over match welds plastic η -factor evaluated for non-hardening material model are lower while for under match welds use of non-hardening material model gives higher value as compare to that of hardening material model. However, it was observed that for over match welds use of ASTM based plastic η -factors (valid for homogeneous specimens) gives the higher values than actual plastic η -factors (evaluated for both hardening as well as non-hardening material model) of mismatch welded specimens. This in turn would lead to un-conservative estimate of fracture toughness and vice versa is true for under-matched welds. (author)

  15. Influence of side-groove root radius on the ductile fracture toughness of miniature C(T) specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Scibetta, M.

    2009-05-15

    The use of miniature C(T) specimens, MC(T), for fracture toughness measurements in the upper shelf regime has been investigated at SCK-CEN since 2004, in the framework of the Electrabel/Tractebel SCK-CEN Convention (now General Framework Agreement SUEZ-SCK-CEN). This geometry has been used and validated on both unirradiated (2004-05) and irradiated (2006) materials, mainly reactor pressure vessel (RPV) steels. While side-grooved MC(T) specimens have shown in all conditions a systematically lower tearing resistance and ductile crack initiation toughness as compared to standard-size 1TC(T) samples, the only plain-sided MC(T) specimen tested in 2005 exhibited very high ductile fracture toughness, thus pointing at a strong influence of side-grooving on the upper shelf properties of MC(T) specimens. This study investigates the influence of side-grooving on the initiation toughness and tearing resistance of MC(T) specimens, as a function of the root radius of the side-groove (ranging from 0.1 to 1 mm) and in comparison with plain-sided MC(T) and reference 1TC(T) samples. The material used is the well characterized DIN 22NiMoCr37 RPV steel, which had been used in the European project which generated the famous EURO fracture toughness data set.

  16. High-Throughput Testing of Urogenital and Extragenital Specimens for Detection of Chlamydia Trachomatis and Neisseria Gonorrhoeae with Cobas® CT/NG.

    Science.gov (United States)

    Marlowe, Elizabeth M; Hardy, David; Krevolin, Mark; Gohl, Peter; Bertram, Alexander; Arcenas, Rodney; Seiverth, Britta; Schneider, Tanja; Liesenfeld, Oliver

    2017-09-01

    We compared the analytical and clinical performance of cobas ® CT/NG for use on the Cobas ® 6800/8800 Systems with the Cobas ® 4800 CT/NG Test from urogenital and extragenital specimens in over 12,000 specimens from both male and female subjects in Germany and the United States. The analytical sensitivity was ≤40 EB/ml for Chlamydia trachomatis (CT) and ≤1 CFU/ml for Neisseria gonorrhoeae (NG). Using clinical specimens, the overall percent agreement with the Cobas ® 4800 CT/NG Test was >98.5%. Across urogenital specimens, there were 93 discrepant specimens; 76 (93.8%) of 81 CT discrepant specimens were 6800+/4800- and 10 (83.3%) of 12 NG discrepant specimens were 6800+/4800-. Sequencing verified CT results for 45 (61.6%) of 73 samples positive by 6800 and 1 (20%) of 5 positive by 4800. Similarly, 7 (70.0%) of 10 NG samples positive by 6800 and 1 of 2 positive by 4800 were confirmed by sequencing. Among discrepant extragenital specimens (all 6800+/4800-), 7 (50%) of 14 oropharyngeal and 23 (76.7%) of 30 anorectal CT discordant samples were confirmed as CT positive by sequencing; all 8 anorectal and 20 (90.9%) of 22 oropharyngeal NG discordant results were also confirmed as NG positive. In conclusion, Cobas ® CT/NG for use on the Cobas ® 6800/8800 Systems provides high-throughput automated solutions for sexually transmitted infection (STI) screening programs.

  17. The expressions of P53 protein and proliferating cell nuclear antigen in specimens by CT-guidance percutaneous lung biopsy

    International Nuclear Information System (INIS)

    Zhuang Yiping; Shen Zongli; Zhang Jin; Kang Zheng; Zhu Yueqing; Feng Yong; Shen Wenrong; Wang Yaping

    2004-01-01

    Objective: To evaluate relations between lung cancer and the expressions of P53 protein together with proliferating cell nuclear antigen (PCNA) in specimens of lung lesions by needle biopsy. Methods: CT-guidance percutaneous biopsy of lung lesions were performed in 66 patients with the determination of expressions of p53 protein and PCNA by flow cytometer (FCM). Results: 1. The sensitivity of CT-guidance percutaneous biopsy was 94.3% in 53 cases of lung cancer with the diagnostic accuracy of 90.9% totally. The complication rate of pneumothorax was 4.6%. 2. The expression of P53 protein was (29.9 ± 2.7)% in lung cancer (53 cases), while (17.9 ± 2.8)% in benign lesions (13 cases) (t=2.0, P 2 =6.10, P 2 =9.71, P 0.05). Conclusions: FCM plays and valuable role in determining the expression of P53 protein and PCNA in the specimen of lung cancer by CT-guided percutaneous biopsy. The expression of p53 and PCNA may be useful in the diagnosis of lung cancer by providing the relation between imaging of lung cancer and the molecular mechanism, and furthermore revealing the characteristics of molecular biology of lung cancer at protein level. (authors)

  18. Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens

    International Nuclear Information System (INIS)

    Nevalainen, M.; Dodds, R.H. Jr.

    1996-07-01

    This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised η-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front

  19. CT-Guided Transthoracic Core Biopsy for Pulmonary Tuberculosis: Diagnostic Value of the Histopathological Findings in the Specimen

    International Nuclear Information System (INIS)

    Fukuda, Hozumi; Ibukuro, Kenji; Tsukiyama, Toshitaka; Ishii, Rei

    2004-01-01

    We evaluated the value of CT-guided transthoracic core biopsy for the diagnosis of mycobacterial pulmonary nodules. The 30 subjects in this study had pulmonary nodules that had been either diagnosed histopathologically as tuberculosis or were suspected as tuberculosis based on a specimen obtained by CT-guided transthoracic core biopsy. The histopathological findings, the existence of acid-fast bacilli in the biopsy specimens, and the clinical course of the patients after the biopsy were reviewed retrospectively. Two of the three histological findings for tuberculosis that included epithelioid cells, multinucleated giant cells and caseous necrosis were observed in 21 of the nodules which were therefore diagnosed as histological tuberculosis. Six of these 21 nodules were positive for acid-fast bacilli, confirming the diagnosis of tuberculosis. Thirteen of the 21 nodules did not contain acid-fast bacilli but decreased in size in response to antituberculous treatment and were therefore diagnosed as clinical tuberculosis. Seven nodules with only caseous necrosis were diagnosed as suspected tuberculosis, with a final diagnosis of tuberculosis being made in 4 of the nodules and a diagnosis of old tuberculosis in 2 nodules. Two nodules with only multinucleated giant cells were diagnosed as suspected tuberculosis with 1 of these nodules being diagnosed finally as tuberculosis and the other nodule as a nonspecific granuloma. When any two of the three following histopathological findings - epithelioid cells, multinucleated giant cells or caseous necrosis - are observed in a specimen obtained by CT-guided transthoracic core biopsy, the diagnosis of tuberculosis can be established without the detection of acid-fast bacilli or Mycobacterium tuberculosis

  20. A semiautomatic CT-based ensemble segmentation of lung tumors: comparison with oncologists' delineations and with the surgical specimen.

    Science.gov (United States)

    Rios Velazquez, Emmanuel; Aerts, Hugo J W L; Gu, Yuhua; Goldgof, Dmitry B; De Ruysscher, Dirk; Dekker, Andre; Korn, René; Gillies, Robert J; Lambin, Philippe

    2012-11-01

    To assess the clinical relevance of a semiautomatic CT-based ensemble segmentation method, by comparing it to pathology and to CT/PET manual delineations by five independent radiation oncologists in non-small cell lung cancer (NSCLC). For 20 NSCLC patients (stages Ib-IIIb) the primary tumor was delineated manually on CT/PET scans by five independent radiation oncologists and segmented using a CT based semi-automatic tool. Tumor volume and overlap fractions between manual and semiautomatic-segmented volumes were compared. All measurements were correlated with the maximal diameter on macroscopic examination of the surgical specimen. Imaging data are available on www.cancerdata.org. High overlap fractions were observed between the semi-automatically segmented volumes and the intersection (92.5±9.0, mean±SD) and union (94.2±6.8) of the manual delineations. No statistically significant differences in tumor volume were observed between the semiautomatic segmentation (71.4±83.2 cm(3), mean±SD) and manual delineations (81.9±94.1 cm(3); p=0.57). The maximal tumor diameter of the semiautomatic-segmented tumor correlated strongly with the macroscopic diameter of the primary tumor (r=0.96). Semiautomatic segmentation of the primary tumor on CT demonstrated high agreement with CT/PET manual delineations and strongly correlated with the macroscopic diameter considered as the "gold standard". This method may be used routinely in clinical practice and could be employed as a starting point for treatment planning, target definition in multi-center clinical trials or for high throughput data mining research. This method is particularly suitable for peripherally located tumors. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. Characterization of test specimens produced in reduced size for X-ray microtomography (µ-CT tests

    Directory of Open Access Journals (Sweden)

    E. E. BERNARDES

    Full Text Available Abstract The need to use reduced sample sizes, in order to attain improved spatial resolution in (µ-CT tests applied in Portland cement composites, makes researchers perform the fractionation of materials to obtain samples with dimensions compatible with the capacity of the scanning equipment, which might cause alterations in the microstructure under analysis. Therefore, a test specimen (TS with dimensions compatible with the scanning capacity of a microtomography system that operates with an X-ray tube and voltage ranging from 20 to 100 kV was proposed. Axial compression strength tests were made and their total porosity was assessed by an apparent density and solid fraction density ratio, which were obtained by means of mercury and helium pycnometry and µ-CT technique, respectively. The adoption of that TS has shown to be viable for providing a sample with a higher level of representation.

  2. Comparison of fracture toughness values from large-scale pipe system tests and C(T) specimens

    International Nuclear Information System (INIS)

    Olson, R.; Scott, P.; Marschall, C.; Wilkowski, G.

    1993-01-01

    Within the International Piping Integrity Research Group (IPIRG) program, pipe system experiments involving dynamic loading with intentionally circumferentially cracked pipe were conducted. The pipe system was fabricated from 406-mm (16-inch) diameter Schedule 100 pipe and the experiments were conducted at 15.5 MPa (2,250 psi) and 288 C (550 F). The loads consisted of pressure, dead-weight, thermal expansion, inertia, and dynamic anchor motion. Significant instrumentation was used to allow the material fracture resistance to be calculated from these large-scale experiments. A comparison of the toughness values from the stainless steel base metal pipe experiment of standard quasi-static and dynamic C(T) specimen tests showed the pipe toughness value was significantly lower than that obtained from C(T) specimens. It is hypothesized that the cyclic loading from inertial stresses in this pipe system experiment caused local degradation of the material toughness. Such effects are not considered in current LBB or pipe flaw evaluation criteria. 4 refs., 14 figs., 1 tab

  3. Accuracy of spiral CT and 3D reconstruction in the detection of acute pulmonary embolism - development of an animal model using porcine lungs and technical specimens. Development of an animal model using porcine lungs and technical specimens

    International Nuclear Information System (INIS)

    Ries, B.G.; Kauczor, H.U.; Thelen, M.; Konerding, M.A.

    2001-01-01

    Purpose: To develop a model for simulation the CT morphologic situation of acute pulmonary embolism, to evaluate the accuracy of spiral CT and 3D reconstruction in the detection of artificial emboli and to investigate the influence of the orientation of emboli depending on z-axis orientation. Materials and Methods: Standardized artificial emboli made of wax and of defined size and shape were positioned into the pulmonary arteries of porcine lungs. Castings of the embolized pulmonary arterial trees were made by injection of a special opaque resin. After performance of spiral CT the data sets of the emboli and the pulmonary arteries were post-processed. The 3D segmentations were compared with the anatomic preparation to evaluate the accuracy of spiral CT/3D reconstruction-technique. Technical specimens simulating CT-morphology of acute embolized vessels underwent spiral CT in six different positions with respect to the z-axis. The CT data were reconstructed using a standardized and a contrastadapted method with interactive correction. The 3D emboli were analysed under qualitative aspects, and measurements of their extent were done. Results: In nearly 91%, there was complete agreement between CT and the corresponding findings at the anatomical preparation. Measurements of the 3D reconstructed technical specimens showed discrepancies of shape and size in dependence of the size of the original preparation, orientation and reconstruction technique. Overestimation up to 4 mm and underestimation to 2,2 mm were observed. Measurements of preparations with heights from 14 to 26 mm showed variances of ±1,5 mm (∝6-11%). Conclusion: The presented models are suitable to simulate CT morphology of acute pulmonary embolism under ex-vivo conditions. Accuracy in the detection of artificial emboli using spiral CT/3D reconstruction is affected by localization, size and orientation of the emboli and the reconstruction technique. (orig.) [de

  4. CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

    International Nuclear Information System (INIS)

    Karlo, C.; Reiner, C.S.; Stolzmann, P.; Breitenstein, S.; Marincek, B.; Weishaupt, D.; Frauenfelder, T.

    2010-01-01

    Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

  5. Comparative study of residual stress by table of coordinates and X-ray diffraction in a welded joint

    International Nuclear Information System (INIS)

    Siqueira Filho, A.V.; Rolim, T.L.; Yadava, Y.P.; Ferreira, R.A.S.; Guimaraes, P.B.

    2010-01-01

    Residual stresses in a welded joint of naval steel ASTM AH-32 was measured either by the displacements of referenced points with a coordinated table (CT) or by x-ray diffraction (X-DR) after welding. For all tests, the welding was performed by a certified welder in the SMAW process, using an AWS E 7018 G3 electrode. Before welding, small holes evenly spaced were made in the specimens to be mapped on a coordinated table (CT). After labeling, the specimens were submitted to the welding process and new measurements by (CT) to evaluate the displacements produced by the tensions generated. In parallel, residual stress were measured by DR-X for validation of this new measurement methodology. (author)

  6. Biaxial Creep Specimen Fabrication

    International Nuclear Information System (INIS)

    JL Bump; RF Luther

    2006-01-01

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments

  7. Biaxial Creep Specimen Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    JL Bump; RF Luther

    2006-02-09

    This report documents the results of the weld development and abbreviated weld qualification efforts performed by Pacific Northwest National Laboratory (PNNL) for refractory metal and superalloy biaxial creep specimens. Biaxial creep specimens were to be assembled, electron beam welded, laser-seal welded, and pressurized at PNNL for both in-pile (JOYO reactor, O-arai, Japan) and out-of-pile creep testing. The objective of this test campaign was to evaluate the creep behavior of primary cladding and structural alloys under consideration for the Prometheus space reactor. PNNL successfully developed electron beam weld parameters for six of these materials prior to the termination of the Naval Reactors program effort to deliver a space reactor for Project Prometheus. These materials were FS-85, ASTAR-811C, T-111, Alloy 617, Haynes 230, and Nirnonic PE16. Early termination of the NR space program precluded the development of laser welding parameters for post-pressurization seal weldments.

  8. Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

    Science.gov (United States)

    Taylor, Stuart A; Halligan, Steve; Bartram, Clive I; Morgan, Paul R; Talbot, Ian C; Fry, Nicola; Saunders, Brian P; Khosraviani, Kirosh; Atkin, Wendy

    2003-10-01

    To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon. Copyright RSNA, 2003

  9. Phased Array Ultrasonic Examination of Reactor Coolant System (Carbon Steel-to-CASS) Dissimilar Metal Weld Mockup Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, S. L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cinson, A. D. [US Nuclear Regulatory Commission (NRC), Washington, DC (United States); Diaz, A. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, M. T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-23

    In the summer of 2009, Pacific Northwest National Laboratory (PNNL) staff traveled to the Electric Power Research Institute (EPRI) NDE Center in Charlotte, North Carolina, to conduct phased-array ultrasonic testing on a large bore, reactor coolant pump nozzle-to-safe-end mockup. This mockup was fabricated by FlawTech, Inc. and the configuration originated from the Port St. Lucie nuclear power plant. These plants are Combustion Engineering-designed reactors. This mockup consists of a carbon steel elbow with stainless steel cladding joined to a cast austenitic stainless steel (CASS) safe-end with a dissimilar metal weld and is owned by Florida Power & Light. The objective of this study, and the data acquisition exercise held at the EPRI NDE Center, were focused on evaluating the capabilities of advanced, low-frequency phased-array ultrasonic testing (PA-UT) examination techniques for detection and characterization of implanted circumferential flaws and machined reflectors in a thick-section CASS dissimilar metal weld component. This work was limited to PA-UT assessments using 500 kHz and 800 kHz probes on circumferential flaws only, and evaluated detection and characterization of these flaws and machined reflectors from the CASS safe-end side only. All data were obtained using spatially encoded, manual scanning techniques. The effects of such factors as line-scan versus raster-scan examination approaches were evaluated, and PA-UT detection and characterization performance as a function of inspection frequency/wavelength, were also assessed. A comparative assessment of the data is provided, using length-sizing root-mean-square-error and position/localization results (flaw start/stop information) as the key criteria for flaw characterization performance. In addition, flaw signal-to-noise ratio was identified as the key criterion for detection performance.

  10. Changes in measured size of atherosclerotic plaque calcifications in dual-energy CT of ex vivo carotid endarterectomy specimens: effect of monochromatic keV image reconstructions

    International Nuclear Information System (INIS)

    Mannelli, Lorenzo; Mitsumori, Lee M.; Ferguson, Marina; Xu, Dongxiang; Chu, Baocheng; Branch, Kelley R.; Shuman, William P.; Yuan, Chun

    2013-01-01

    The aim of this study was to compare the size of the calcifications measured on the different keV images to a histological standard. Five ex vivo carotid endarterectomy (CEA) specimens were imaged with a dual-energy CT. CT images were reconstructed at different monochromatic spectral energies (40, 60, 77, 80, 100, 120, 140 keV). Cross-sectional area of the plaque calcifications present on each CT image was measured. The histological calcium areas on each corresponding CEA specimen were traced manually on digitised images of Toluidine Blue/Basic Fuchsin stained plastic sections. The CT images and corresponding histology sections were matched. The CT-derived calcium areas on each keV image were compared to the calcified area measurements by histology. A total of 107 histology sections were matched to corresponding CT images. The average calcified area per section by histology was 7.6 ± 7 mm 2 (range 0-26.4 mm 2 ). There was no significant difference between the calcified areas measured by histology and those measured on CT-virtual monochromatic spectral (VMS) reconstructed images at 77 keV (P = 0.08), 80 keV (P = 0.20) and 100 keV (P = 0.14). Calcium area measured on the 80 keV image set was most comparable to the amount of calcium measured by histology. (orig.)

  11. The laser beam welding test of ODS fuel claddings

    International Nuclear Information System (INIS)

    Uwaba, Tomoyuki; Ukai, Shigeharu

    2004-06-01

    As a alternative method of pressurized resistance welding being currently developed, integrity evaluations for a laser beam welding joint between a ODS cladding tube and a FMS end plug were conducted for the purpose of studying the applicability of the laser beam welding technique to the welding with the lower end plug. The laser beam welding causes blowholes in the welding zone, whose effect on the high cycle fatigue strength of the joint is essential because of the flow-induced vibration during irradiation. The rotary bending tests using specimens with laser beam welding between ODS cladding tubes and FMS end plugs were carried out to evaluate the fatigue strength of the welding joint containing blowholes. The fatigue limit of stress amplitude about 200 MPa from 10 6 -10 7 cycles suggested that the laser beam welding joint had enough strength against the flow-induced vibration. Sizing of blowholes in the welding zone by using a micro X ray CT technique estimated the rate of defect areas due to blowholes at 1-2%. It is likely that the fatigue strength remained nearly unaffected by blowholes because of the no correlation between the breach of the rotary bending test specimen and the rate of defect area. Based on results of tensile test, internal burst test, Charpy impact test and fatigue test of welded zone, including study of allowable criteria of blowholes in the inspection, it is concluded that the laser beam welding can be probably applied to the welding between the ODS cladding tube and the FMS lower end plug. (author)

  12. Comparative study on Charpy specimen reconstitution techniques

    International Nuclear Information System (INIS)

    Bourdiliau, B.; Decroix, G.-M.; Averty, X.; Wident, P.; Bienvenu, Y.

    2011-01-01

    Highlights: → Welding processes are used to reconstitute previously tested Charpy specimens. → Stud welding is preferred for a quick installation, almost immediately operational. → Friction welding produces better quality welds, but requires a development effort. - Abstract: Reconstitution techniques are often used to allow material from previously fractured Charpy-V specimens to be reused for additional experiments. This paper presents a comparative experimental study of various reconstitution techniques and evaluates the feasibility of these methods for future use in shielded cells. The following techniques were investigated: arc stud welding, 6.0 kW CO 2 continuous wave laser welding, 4.5 kW YAG continuous wave laser welding and friction welding. Subsize Charpy specimens were reconstituted using a 400 W YAG pulsed wave laser. The best result was obtained with arc stud welding; the resilience of the reconstituted specimens and the load-displacement curves agreed well with the reference specimens, and the temperature elevation caused by the welding process was limited to the vicinity of the weld. Good results were also obtained with friction welding; this process led to the best quality welds. Laser welding seems to have affected the central part of the specimens, thus leading to different resilience values and load-displacement curves.

  13. Study of creep crack growth behavior of 316LN welds

    International Nuclear Information System (INIS)

    Venugopal, S.; Kumar, Yatindra; Sasikala, G.

    2016-01-01

    Creep crack growth (CCG) behavior plays an important role in the assessment of structural integrity of components operating at elevated temperature under load/stress condition. Integrity of the welded components is decided primarily by that of the weld. Creep crack growth behavior of 316LN welds prepared using consumables developed indigenously for welding the 316L(N) SS components for the Prototype Fast Breeder Reactor has been studied. The composition of the consumable is tailored to ensure about 5 FN (ferrite number) of δ ferrite in the weld deposit. Constant load CCG tests were carried out as per ASTM E1457 at different applied loads at temperatures in the range 823-923 K on CT specimens fabricated from 'V-type' weld joints with notch in the weld centre. The creep crack growth rate (α) is commonly correlated to a time dependent fracture mechanics parameter known as C*. The α3-C* correlations (α=D(C*) φ ) were established in the temperature range 823-923 K. The crack growth rates at different temperature have been compared with that given in RCC-MR. Extensive microstructural and fractographic studies using optical and scanning electron microscopy were carried out on the CCG tested specimens to understand the effect of transformation of delta ferrite on the creep damage and fracture mechanisms associated with CCG in the weld metal at different test conditions. (author)

  14. Study of oxide film formed in a pre cracked CT specimen of AISI 304L during a rising displacement test in 288 C water

    International Nuclear Information System (INIS)

    Diaz S, A.; Castano M, V.

    2007-01-01

    A study of oxide film formed inside pre cracked CT specimens during a rising displacement test in high temperature water (288 C) was performed in this study, The environmental conditions used during the experiments were similar to these found in Boiling Water Reactors (BWR): Normal Water Condition (NWC - 200 ppb O 2 ) and Hydrogen Water Chemistry (HWC - 125 ppb H2). The oxide films formed were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). In both cases the oxide film consisted of two layers identified as magnetite. In the case of HWC the results agree with previous reports that mention magnetite as a stable phase in reducing conditions. However the stable phase in oxidant conditions is hematite and this work shows the presence of magnetite crystals in the narrow crack of CT specimens in spite of the oxidant environmental condition. This situation confirms that inside the pre-cracked CT specimens the environmental conditions were different from the oxidant bulk, and probably a poor oxygen access and stagnant conditions within the narrow crack promoted a localized reducing environment that permitted the magnetite formation. Is evident that the crack growth studies should consider the conditions inside crack because they are significantly different. (Author)

  15. Comparative study of residual stress by table of coordinates and X-ray diffraction in a welded joint; Estudo comparativo das tensoes residuais por mesa de coordenadas e DR-X numa junta soldada

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira Filho, A.V.; Rolim, T.L.; Yadava, Y.P.; Ferreira, R.A.S., E-mail: anibal_siqueira@yahoo.com.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica; Cardoso, F.I.B. [Universidade de Pernambuco (POLI/UPE), Recife, PE (Brazil); Guimaraes, P.B. [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil)

    2010-07-01

    Residual stresses in a welded joint of naval steel ASTM AH-32 was measured either by the displacements of referenced points with a coordinated table (CT) or by x-ray diffraction (X-DR) after welding. For all tests, the welding was performed by a certified welder in the SMAW process, using an AWS E 7018 G3 electrode. Before welding, small holes evenly spaced were made in the specimens to be mapped on a coordinated table (CT). After labeling, the specimens were submitted to the welding process and new measurements by (CT) to evaluate the displacements produced by the tensions generated. In parallel, residual stress were measured by DR-X for validation of this new measurement methodology. (author)

  16. Irradiation effects on fracture toughness of two high-copper submerged-arc welds, HSSI series 5

    International Nuclear Information System (INIS)

    Nanstad, R.K.; Haggag, F.M.; McCabe, D.E.; Iskander, S.K.; Bowman, K.O.; Menke, B.H.

    1992-10-01

    The Fifth Irradiation Series in the Heavy-Section Steel irradiation (HSSI) Program was aimed at obtaining a statistically significant fracture toughness data base on two weldments with high-copper contents to determine the shift and shape of the K lc curve as a consequence of irradiation. The program included irradiated Charpy V-notch impact, tensile, and drop-weight specimens in addition to compact fracture toughness specimens. Compact specimens with thicknesses of 25.4, 50.8, and 101.6 mm [1T C(T), 2T C(T), and 4T C(T), respectively] were irradiated. Additionally, unirradiated 6T C(T) and 8T C(T) specimens with the same K lc measuring capacity as the irradiated specimens were tested. The materials for this irradiation series were two weldments fabricated from special heats of weld wire with copper added to the melt. One lot of Linde 0124 flux was used for all the welds. Copper levels for the two welds are 0.23 and 0.31 wt %, while the nickel contents for both welds are 0.60 wt %. Twelve capsules of specimens were irradiated in the pool-side facility of the Oak Ridge Research Reactor at a nominal temperature of 288 degree C and an average fluence of about 1.5 x 10 19 neutrons/cm 2 (> 1 MeV). This volume, Appendices E and F, contains the load-displacement curves and photographs of the fracture toughness specimens from the 72W weld (0.23 wt % Cu) and the 73 W weld (0.31 wt % Cu), respectively

  17. Effect of nickel content on mechanical properties and fracture toughness of weld metal of WWER-1000 reactor vessel welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Zubchenko, A.S.; Vasilchenko, G.S.; Starchenko, E.G.; Nosov, S.I

    2004-08-01

    Welding of WWER-1000 reactor vessel of steel 15X2HMPHIA is performed using the C{sub B}-12X2H2MAA wire and PHI-16 or PHI-16A flux. Nickel content in the weld metal usually lays within the limits 1.2-1.9%. The experimental data is shown on the weld metal with the nickel contents 1.28-2.45% after irradiation with fluence up to 260.10{sup 22}n/m{sup 2} at energy more than 0.5 MEV. The embrittlement was measured by shift of critical brittleness temperature. Has appeared, that the weld metal with the low nickel content is the least responsive to irradiation embrittlement. The mechanical properties and fracture toughness of the weld metal with the contents of a nickel less than 1.3% are studied. Specimens CT-1T are tested, the 'master-curve', and its confidence bounds with probability of destruction 5 and 95% is built. 'Master-curve' in the specified confidence interval is affirmed by CT-4T specimens test data. Is shown, that the mechanical properties and fracture toughness of the weld metal with the contents of nickel less than 1.3% satisfy the normative requirements.

  18. Effect of nickel content on mechanical properties and fracture toughness of weld metal of WWER-1000 reactor vessel welded joints

    International Nuclear Information System (INIS)

    Zubchenko, A.S.; Vasilchenko, G.S.; Starchenko, E.G.; Nosov, S.I.

    2004-01-01

    Welding of WWER-1000 reactor vessel of steel 15X2HMPHIA is performed using the C B -12X2H2MAA wire and PHI-16 or PHI-16A flux. Nickel content in the weld metal usually lays within the limits 1.2-1.9%. The experimental data is shown on the weld metal with the nickel contents 1.28-2.45% after irradiation with fluence up to 260.10 22 n/m 2 at energy more than 0.5 MEV. The embrittlement was measured by shift of critical brittleness temperature. Has appeared, that the weld metal with the low nickel content is the least responsive to irradiation embrittlement. The mechanical properties and fracture toughness of the weld metal with the contents of a nickel less than 1.3% are studied. Specimens CT-1T are tested, the 'master-curve', and its confidence bounds with probability of destruction 5 and 95% is built. 'Master-curve' in the specified confidence interval is affirmed by CT-4T specimens test data. Is shown, that the mechanical properties and fracture toughness of the weld metal with the contents of nickel less than 1.3% satisfy the normative requirements

  19. Fracture toughness assessment of in-service aged primary circuit elbows using mini C(T) specimens taken from outer skin

    International Nuclear Information System (INIS)

    Jayet-Gendrot, S.; Meylogan, T.; Ould, P.

    1995-05-01

    Type CF8M cast duplex stainless steels used in the primary circuit elbows of pressurized water reactors are subject to thermal aging embrittlement at their service temperature, around 300 deg. C. This phenomenon affects their fracture toughness properties. In order to assess the residual fracture toughness of these elbows, estimations are made through predictive formulae based on chemical composition and aging conditions, which provide safe values. However, in the case of the most sensitive materials, it is important to obtain more accurate estimations. A new method of determination was thus considered, based on the testing of mini-CT specimens taken from the skin of in-service elbows. The feasibility of using mini-CT specimens to evaluate the tearing resistance of cast duplex stainless steels seems at first sight difficult, in particular because of the very coarse metallurgical structure of these steels: will small specimens be representative of larger volumes (mainly regular T-CT specimens) and will they not induce too much scatter ? In order to answer such questions, an experimental validation program has been undertaken: the completed program shows that the method is relevant and leads to proposed guidelines which aim at optimizing the experimental results analysis. Then the method is applied to an in-service elbow: the results obtained are found to be in good agreement with the toughness estimations given by our predictive formulae. This subsequently contributes to the validation of the general methodology used for the justification of French primary circuit elbows. (authors). 7 refs., 4 figs., 5 tabs

  20. Annealing effects in low upper-shelf welds (series 9)

    International Nuclear Information System (INIS)

    Iskander, S.K.; Nanstad, R.K.

    1995-01-01

    The purpose of the Ninth Irradiation Series is to evaluate the correlation between fracture toughness and CVN impact energy during irradiation, annealing, and reirradiation (IAR). Results of annealing CVN specimens from the low-USE welds from the Midland beltline and nozzle course welds, as well as HSST plate 02 and HSSI weld 73W are given. Also presented is the effect of annealing on the initiation fracture toughness of annealed material from Midland beltline weld and HSST plate 02. The results from capsule 10-5 specimens of weld 73W confirm those previously obtained on the so-called undersize specimens that were irradiated in the Fifth Irradiation Series, namely that the recovery due to annealing at 343 degrees C (650 degrees F) for 1 week is insignificant. The fabrication of major components for the IAR facility for two positions on the east side of the FNR at the University of Michigan has begun. Fabrication of two reusable capsules (one for temperature verification and the other for dosimetry verification), as well as two capsules for IAR, studies is also under way. The design of a reusable capsule capable of reirradiating previously irradiated and annealed CVN and 1T C(T) specimens is also progressing. The data acquisition and control (DAC) instrumentation for the first two IAR facilities is essentially complete and awaiting completion of the IAR facilities and temperature test capsule for checkout and control algorithm development

  1. Ga-68 DOTATOC PET/CT-Guided Biopsy and Cryoablation with Autoradiography of Biopsy Specimen for Treatment of Tumor-Induced Osteomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Maybody, Majid, E-mail: maybodym@mskcc.org [Memorial Sloan Kettering Cancer Center, Interventional Radiology Service (United States); Grewal, Ravinder K. [Memorial Sloan Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Healey, John H. [Memorial Sloan Kettering Cancer Center, Orthopedic Surgical Oncology Service, Department of Surgery (United States); Antonescu, Cristina R. [Memorial Sloan Kettering Cancer Center, Department of Pathology (United States); Fanchon, Louise [Memorial Sloan Kettering Cancer Center, Department of Physics (United States); Hwang, Sinchun [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States); Carrasquillo, Jorge A. [Memorial Sloan Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Kirov, Assen [Memorial Sloan Kettering Cancer Center, Department of Physics (United States); Farooki, Azeez [Memorial Sloan Kettering Cancer Center, Department of Medicine (United States)

    2016-09-15

    Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by small benign tumors of mesenchymal origin also known as phosphaturic mesenchymal tumors mixed connective tissue variant. Excellent prognosis is expected with eradication of the culprit tumor. These small tumors are notoriously difficult to localize with conventional imaging studies; this often leads to an extensive work up and prolonged morbidity. We report a patient with clinical diagnosis of TIO whose culprit tumor was localized with Ga-68 DOTATOC PET/CT and MRI. Biopsy and cryoablation were performed under Ga-68 DOTATOC PET/CT guidance. Autoradiography of the biopsy specimen was performed and showed in situ correlation between Ga-68 DOTATOC uptake and histopathology with millimeter resolution.

  2. Multifocal Colonic Lesions Detected by {sup 18}F-FDG PET/CT: Correlation with Histopathology and Gross Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byung Wook; Kim, Sung Hoon; Kim, Hae Won; Won, Kyoung Sook; Zeon, Seok Kil [Keimyung University School of Medicine, DaeKolecular Imaging, Daegu (Korea, Republic of)

    2010-09-15

    A fluorodeoxyglucose (FDG) positron emission tomography (PET)-computer tomography (CT) scan for staging. No definite abnormal FDG uptake of the stomach was shown. Incidentally, variable FDG uptake at the bilateral serrates muscles, abdominal muscles and muscles of both thighs (Fig. 1) was observed. He had no significant past medical history except recently diagnosed stomach cancer. On personal interview, he described having had sexual activity the night before the F-18 FDG PET/CT scan, although he was aware of needing to avoid physical activity before a PET scan. The F-18 FDG PET/CT scan was done at 2:00 p.m. Therefore, the hypermetabolism of individual skeletal muscles following sexual activity lasted over 12 h. This case illustrates the hypermetabolism of skeletal muscles following sexual activity as a normal variation.

  3. Multifocal Colonic Lesions Detected by 18F-FDG PET/CT: Correlation with Histopathology and Gross Specimen

    International Nuclear Information System (INIS)

    Choi, Byung Wook; Kim, Sung Hoon; Kim, Hae Won; Won, Kyoung Sook; Zeon, Seok Kil

    2010-01-01

    A fluorodeoxyglucose (FDG) positron emission tomography (PET)-computer tomography (CT) scan for staging. No definite abnormal FDG uptake of the stomach was shown. Incidentally, variable FDG uptake at the bilateral serrates muscles, abdominal muscles and muscles of both thighs (Fig. 1) was observed. He had no significant past medical history except recently diagnosed stomach cancer. On personal interview, he described having had sexual activity the night before the F-18 FDG PET/CT scan, although he was aware of needing to avoid physical activity before a PET scan. The F-18 FDG PET/CT scan was done at 2:00 p.m. Therefore, the hypermetabolism of individual skeletal muscles following sexual activity lasted over 12 h. This case illustrates the hypermetabolism of skeletal muscles following sexual activity as a normal variation.

  4. Comparison of fracture toughness values from an IPIRG-1 large-scale pipe system test and C(T) specimens on wrought TP304 stainless steel

    International Nuclear Information System (INIS)

    Olson, R.J.; Scott, P.; Marschall, C.W.; Wilkowski, G.M.

    1994-01-01

    Within the First International Piping Integrity Research Group (IPIRG-1) program, pipe system experiments involving dynamic loading with intentionally circumferentially cracked pipe were conducted. The pipe system was fabricated from 406-mm (16-inch) diameter Schedule 100 pipe, and the experiments were conducted at a pressure of 15.5 MPa (2,250 psi) and 288 C (550 F). The loads consisted of pressure, dead-weight, thermal expansion, inertia, and dynamic anchor motion. Significant instrumentation was used to allow the material fracture resistance to be calculated from these large-scale experiments. Three independent analyses were used to calculate the toughness directly from one of these pipe experiments. A comparison of the toughness values from the stainless steel base metal pipe experiment to standard quasi-static and dynamic C(T) specimen tests showed the pipe toughness value was significantly lower than that obtained from C(T) specimens. It is hypothesized that the cyclic loading from inertial stresses in this pipe system experiment caused local degradation of the material toughness. Such effects are not considered in current LBB or pipe flaw evaluation criteria

  5. Fracture toughness master curve characterization of Linde 1092 weld metal for Beaver valley 1 reactor

    International Nuclear Information System (INIS)

    Lee, Bong Sang; Yang, Won Jon; Hong, Jun Hwa

    2000-12-01

    This report summarizes the test results obtained from the Korean contribution to the integrity assessment of low toughness Beaver Valley reactor vessel by characterizing the fracture toughness of Linde 1092 (No. 305414) weld metal. 10 PCVN specimens and 10 1T-CT specimens were tested in accordance with the ASTM E 1921-97 standard, 'Standard test method for determination of reference temperature, T o , for ferritic steels in the transition range'. This results can also be useful for assessment of Linde 80 low toughness welds of Kori-1

  6. Fracture toughness master curve characterization of Linde 1092 weld metal for Beaver valley 1 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong Sang; Yang, Won Jon; Hong, Jun Hwa

    2000-12-01

    This report summarizes the test results obtained from the Korean contribution to the integrity assessment of low toughness Beaver Valley reactor vessel by characterizing the fracture toughness of Linde 1092 (No. 305414) weld metal. 10 PCVN specimens and 10 1T-CT specimens were tested in accordance with the ASTM E 1921-97 standard, 'Standard test method for determination of reference temperature, T{sub o}, for ferritic steels in the transition range'. This results can also be useful for assessment of Linde 80 low toughness welds of Kori-1.

  7. SU-F-J-07: Evaluating the Adequacy of Biopsy Specimens for Genetic Signature Assessment by Measuring the Metabolic Activity in Specimens Obtained Under 18F-FDG PET/CT Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Fanchon, L; Russell, J; Dogan, S; Carlin, S; Pinker-Domenig, K; Yorke, E; Schmidtlein, C. Ross; Fujisawa, S; Manova-Todorova, K; Zanzonico, P; Deasy, J O; Humm, J L; Solomon, S; Kirov, A S [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2016-06-15

    Purpose: Genetic profiling of biopsied tissue is the basis for personalized cancer therapy. However biopsied materials may not contain sufficient amounts of DNA needed for analysis. We propose a method to determine the adequacy of specimens for performing genetic profiling by quantifying metabolic activity. Methods: We measured the response of two radiation detectors to the activity contained in the minimum amount of tumor cells needed for genetic profiling in biopsy specimens obtained under 2-deoxy-2-({sup 18}F)fluoro-D-glucose ({sup 18}F-FDG) PET/CT guidance. The expected tumor cell concentration in biopsy specimens was evaluated from the amount of DNA needed (∼100 µg) and the number of pathology sections typically used for the analysis. The average {sup 18}F-FDG uptake per cell was measured by incubating KPC-4662 pancreatic tumor cells and HT-29 colorectal adenocarcinoma tumor cells in {sup 18}F-FDG containing solution (activity concentrations between 0.0122 and 1.51 MBq/mL and glucose concentrations of 3.1 and 1 g/L) for 1 to 1.75 hours and then measuring the activity of a known number of cells. Measurements of surrogate specimens obtained using 18G needle biopsies of gels containing these cells in expected concentrations (∼10{sup 4} µL{sup −1}) were performed using an autoradiography CCD based device (up to 20 min exposure) and a scintillation well counter (∼1 min measurements) about 3 and 5 hours after the end of incubation respectively. Results: At start of autoradiography there were between 0.16 and 1.5 {sup 18}F-FDG molecules/cell and between 1.14 and 5.43×10{sup 7} {sup 18}F-FDG molecules/mL. For the scintillation well counter, sample to minimum-detectable-count rate ratios were greater than 7 and the counting error was less than 25% for ≤80 s measurement times. Images of the samples were identifiable on the autoradiograph for ∼10 min and longer exposure times. Conclusion: Scintillation well counter measurements and CCD based

  8. Modelling of microstructural creep damage in welded joints of 316L stainless steel

    International Nuclear Information System (INIS)

    Bouche, G.

    2000-01-01

    Welded joints of 316L stainless steel under service conditions at elevated temperature are known to be preferential sites of creep damage, as compared to the base material. This damage results in the formation of cavities and the development of creep cracks which can lead to a premature failure of welded components. The complex two-phase microstructure of 316L welds was simulated by manually filling a mould with longitudinal deposited weld beads. The moulded material was then aged during 2000 hours at 600 deg. C. High resolution Scanning Electron Microscopy was largely used to examine the microstructure of the simulated material before and after ageing. Smooth and notched creep specimens were cut from the mould and tested at 600 deg. C under various stress levels. A comparison of the lifetime versus nominal stress curves for the base and welded materials shows a greater dependence of the welded material to creep phenomena. Observation and EBSD analysis show that damage is preferentially located along the austenite grain boundaries. The stress and strain fields in the notched specimens were calculated by finite element method. A correlation of this field to the observed damage was made in order to propose a predictive law relating the creep damage to the mechanical conditions applied locally. Further mechanical tests and simulation on CT specimens and mode II tubular specimens allowed validating the model under various multiaxial loading conditions. (author)

  9. Homogeneous weldings of copper

    International Nuclear Information System (INIS)

    Campurri, C.; Lopez, M.; Fernandez, R.; Osorio, V.

    1995-01-01

    This research explored the metallurgical and mechanical properties of arc welding of copper related with influence of Argon, Helium and mixtures of them. Copper plates of 6 mm thickness were welded with different mixtures of the mentioned gases. The radiography of welded specimens with 100% He and 100% Ar does not show show any porosity. On the other hand, the copper plates welded different gas mixtures presented uniform porosity in the welded zone. The metallographies show recrystallized grain in the heat affected zone, while the welding zone showed a dendritic structure. The results of the tensile strength vary between a maximum of 227 MPa for 100% He and a minimum of 174 MOa for the mixture of 60% He and 40% Ar. For the elongation after fracture the best values, about 36%, were obtained for pure gases. As a main conclusion, we can say that arc welding of copper is possible without loosing the mechanical and metallurgical properties of base metal. 6 refs

  10. Accuracy of spiral CT and 3D reconstruction in the detection of acute pulmonary embolism - development of an animal model using porcine lungs and technical specimens. Development of an animal model using porcine lungs and technical specimens; Diagnostik der akuten Lungenembolie mittels Spiral-CT und 3D-Rekonstruktion. Entwicklung eines Tiermodells und technischer Probekoerper im Ex-vivo-Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ries, B.G. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Klinik fuer Radiologische Diagnostik, RWTH Aachen (Germany); Kauczor, H.U.; Thelen, M. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Konerding, M.A. [Anatomisches Inst., Mainz Univ (Germany)

    2001-02-01

    Purpose: To develop a model for simulation the CT morphologic situation of acute pulmonary embolism, to evaluate the accuracy of spiral CT and 3D reconstruction in the detection of artificial emboli and to investigate the influence of the orientation of emboli depending on z-axis orientation. Materials and Methods: Standardized artificial emboli made of wax and of defined size and shape were positioned into the pulmonary arteries of porcine lungs. Castings of the embolized pulmonary arterial trees were made by injection of a special opaque resin. After performance of spiral CT the data sets of the emboli and the pulmonary arteries were post-processed. The 3D segmentations were compared with the anatomic preparation to evaluate the accuracy of spiral CT/3D reconstruction-technique. Technical specimens simulating CT-morphology of acute embolized vessels underwent spiral CT in six different positions with respect to the z-axis. The CT data were reconstructed using a standardized and a contrastadapted method with interactive correction. The 3D emboli were analysed under qualitative aspects, and measurements of their extent were done. Results: In nearly 91%, there was complete agreement between CT and the corresponding findings at the anatomical preparation. Measurements of the 3D reconstructed technical specimens showed discrepancies of shape and size in dependence of the size of the original preparation, orientation and reconstruction technique. Overestimation up to 4 mm and underestimation to 2,2 mm were observed. Measurements of preparations with heights from 14 to 26 mm showed variances of {+-}1,5 mm ({proportional_to}6-11%). Conclusion: The presented models are suitable to simulate CT morphology of acute pulmonary embolism under ex-vivo conditions. Accuracy in the detection of artificial emboli using spiral CT/3D reconstruction is affected by localization, size and orientation of the emboli and the reconstruction technique. (orig.) [German] Ziel: Die Entwicklung

  11. Microscopic dual-energy CT (microDECT): a flexible tool for multichannel ex vivo 3D imaging of biological specimens.

    Science.gov (United States)

    Handschuh, S; Beisser, C J; Ruthensteiner, B; Metscher, B D

    2017-07-01

    Dual-energy computed tomography (DECT) uses two different x-ray energy spectra in order to differentiate between tissues, materials or elements in a single sample or patient. DECT is becoming increasingly popular in clinical imaging and preclinical in vivo imaging of small animal models, but there have been only very few reports on ex vivo DECT of biological samples at microscopic resolutions. The present study has three main aims. First, we explore the potential of microscopic DECT (microDECT) for delivering isotropic multichannel 3D images of fixed biological samples with standard commercial laboratory-based microCT setups at spatial resolutions reaching below 10 μm. Second, we aim for retaining the maximum image resolution and quality during the material decomposition. Third, we want to test the suitability for microDECT imaging of different contrast agents currently used for ex vivo staining of biological samples. To address these aims, we used microCT scans of four different samples stained with x-ray dense contrast agents. MicroDECT scans were acquired with five different commercial microCT scanners from four companies. We present a detailed description of the microDECT workflow, including sample preparation, image acquisition, image processing and postreconstruction material decomposition, which may serve as practical guide for applying microDECT. The MATLAB script (The Mathworks Inc., Natick, MA, USA) used for material decomposition (including a graphical user interface) is provided as a supplement to this paper (https://github.com/microDECT/DECTDec). In general, the presented microDECT workflow yielded satisfactory results for all tested specimens. Original scan resolutions have been mostly retained in the separate material fractions after basis material decomposition. In addition to decomposition of mineralized tissues (inherent sample contrast) and stained soft tissues, we present a case of double labelling of different soft tissues with subsequent

  12. Influence of Loading Direction and Weld Reinforcement on Fatigue Performance of TIG Weld Seam

    Directory of Open Access Journals (Sweden)

    HUI Li

    2018-02-01

    Full Text Available The influence of loading direction and weld reinforcement on fatigue performance of TC2 titanium alloy TIG weld seam was investigated via fatigue experiments and SEM fracture observation. The results show that the fatigue life of retaining weld reinforcement specimens is lower than that of removing one in the same weld direction. The fatigue life of oblique weld specimens is higher than that of straight one with the same weld reinforcement treatment. The initiation of removing weld reinforcement specimens' fatigue crack sources is in the hole defect, but the weld reinforcement specimen initiate at the weld toes. During the early stage of fatigue crack propagation, the cracks all grow inside the weld seam metal with obvious fatigue striation. And the fatigue cracks of oblique weld specimens pass through the weld seam into the base with a typical toughness fatigue striation during the last stage of fatigue crack propagation. The dimple of straight weld specimens is little and shallow in the final fracture zone. The oblique weld specimens broke in the base metal area, and the dimple is dense.

  13. 46 CFR 54.05-5 - Toughness test specimens.

    Science.gov (United States)

    2010-10-01

    ... shown in Figure 4 of the specification. Special attention is drawn to the fact that the Charpy Keyhole....090-inch. In preparing weld specimens for dropweight testing, weld reinforcement shall be ground flush...

  14. Welding procedure specification for arc welding of St 52-3N steel plates with covered electrodes

    International Nuclear Information System (INIS)

    Cvetkovski, S.; Slavkov, D.; Magdeski, J.

    2003-01-01

    In this paper the results of approval welding technology for arc welding of plates made of St 52-3N steel are presented. Metal arc welding with covered electrode is used welding process. Test specimens are butt welded in different welding positions P A , P F , P C and P D . Before start welding preliminary welding procedure was prepared. After welding of test specimens non destructive and destructive testing was performed. Obtained results were compared with standard DIN 17100 which concerns to chemical composition and mechanical properties of base material. It was confirmed that in all cases mechanical properties of welded joint are higher than those of base material, so preliminary welding procedure (pWTS) can be accepted as welding procedure specification WPS for metal arc welding of St52-3N steel. (Original)

  15. Toughness study of an under matched welded joint: application to the mechanical integrity of the electron beam welded joint of 6016-T6 aluminium alloy

    International Nuclear Information System (INIS)

    Rekik, Wissal

    2016-01-01

    For the demonstration of the integrity of the most sensitive nuclear components, conventional defects, as cracks for example, must be considered within the design step as required by the nuclear safety authority. This phase is particularly crucial for dimensioning of welded structures. To ensure a conservative prediction, the position of the initial crack within the welded joint must be the most detrimental in fracture behavior. Commonly used analyzes consider homogeneous structure with the behavior of the base metal of the welded joint, considered as the weakest metallurgical zone in the case of an overmatched weld. In contrast, similar analysis is not conservative in case of under matched weld. The thesis contributes by the development of an experimental and numerical methodology allowing the identification of the detrimental metallurgical zone in fracture behavior of an under matched welded joint. The methodology proposed is applied to an electron beam welded joint on al 6061-T6. To reach this goal, the gradient of the mechanical behavior along the welded joint was first identified. This is particularly interesting to conduct an advanced analysis based on a multi material approach. In a second step, the fracture behavior of the welded joint was studied on CT specimen. The transferability of the J integral at initiation was approved on another geometry: this represents an important foundation for the transferability assumption to structure. Finally, a numerical analysis on full scale tube was developed. Residual welding stresses and structural effects were considered. The results demonstrate that the heat affected zone located at 13 mm from the middle of the welded joint is the most detrimental zone for fracture analysis. This contradicts the conventional methods conducted on fracture analysis which consider a conventional defect within the fusion zone. (author) [fr

  16. Torque Measurement of Welding of Endplug-Endplate using Multi-pin Remote Welding System

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung; Park, Geun-Il; Lee, Jung-Won; Song, Kee-Chan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    As fuel bundles in PHWR irradiates, inner pressure in claddings of fuel rods increases owing to outer pressure and fission products of nuclear fissions. Because of leak possibility of welding between cladding and end plug, this welding part connects with safety of nuclear fuel rods. Because of importance of this welding part, weldability of end plug-cladding of nuclear fuel rods is continually researched. Welding method for research and commercialization is classified as melting, solid type welding or resistance welding. End plug cladding welding of nuclear fuel rods in PHWR takes advantage of resistance upset butt welding using multicycle mode. This method makes weld flash and shapes re-entrant corner owing to welding heat due to resistivity, contact resistance of cladding-end plug, and inelasticity deformation due to pressure. Welding part between cladding and end plug receives stresses and makes small cracks. In this study, remote welding system for multi-pin assembly was designed, fabricated and welding specimens of end plug-endplate were made using electrical resistance method. The torques of welding between end plug and endplate were measured. These results on welding current, pressure of main electrode and pressure of branch electrode were analyzed. Weldability between end plug and endplate was confirmed through metallographic examinations. In the future, optimal welding examinations due to welding current, welding pressure and welding time will be performed to improve weldability of end plug-endplate.

  17. Creep deformation behavior of weld metal and heat affected zone on 316FR steel thick plate welded joint

    International Nuclear Information System (INIS)

    Hongo, Hiromichi; Yamazaki, Masayoshi; Watanabe, Takashi; Kinugawa, Junichi; Tanabe, Tatsuhiko; Monma, Yoshio; Nakazawa, Takanori

    1999-01-01

    Using hot-rolled 316FR stainless plate (50 mm thick) and 16Cr-8Ni-2Mo filler wire, a narrow-gap welded joint was prepared by GTAW (gas tungsten arc welding) process. In addition to conventional round bar specimens of base metals and weld metal, full-thickness joint specimens were prepared for creep test. Creep tests were conducted at 550degC in order to examine creep deformation and rupture behavior in the weld metal of the welded joint. Creep strain distribution on the surface of the joint specimen was measured by moire interferometry. In the welded joint, creep strength of the weld metal zone apart from the surface was larger than that in the vicinity of the surface due to repeating heat cycles during welding. Creep strain and creep rate within the HAZ adjacent to the weld metal zone were smaller than those within the base metal zone. Creep rate of the weld metal zone in the welded joint was smaller than that of the weld metal specimen due to the restraint of the hardened HAZ adjacent to the zone. The full-thickness welded joint specimens showed longer lives than weld metal specimens, though the lives of the latter was shorter than those of the base metal (undermatching). In the full-thickness welded joint specimen, crack started from the last pass layer of the weld metal zone and fracture occurred at the zone. From the results mentioned above, in order to evaluate the creep properties of the welded joint correctly, it is necessary to conduct the creep test using the full-thickness welded joint specimen which includes the weakest zones of the weld metal, the front and back sides of the plate. (author)

  18. Plasma spot welding of ferritic stainless steels

    International Nuclear Information System (INIS)

    Lesnjak, A.; Tusek, J.

    2002-01-01

    Plasma spot wedding of ferritic stainless steels studied. The study was focused on welding parameters, plasma and shieldings and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas , i. e. a 98% Ar/2% H 2 gas mixture. Tension-shear strength of plasma-spot welded joint was compared to that of resistance sport welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a large weld sport diameter of the former. Strength of both types of welded joints is approximately the same. (Author) 32 refs

  19. Cu-Fe welding techniques by electromagnetic and electron beam welding processes

    International Nuclear Information System (INIS)

    Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

    2015-01-01

    Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)

  20. {sup 18}F-fluorodeoxyglucose-PET/CT to evaluate tumor, nodal disease, and gross tumor volume of oropharyngeal and oral cavity cancer: comparison with MR imaging and validation with surgical specimen

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, Oliver; Chambron-Pinho, Nicole; Sader, Rober [JW Goethe University, Department of Oromaxillofacial Surgery, Frankfurt (Germany); Middendorp, Markus [JW Goethe University, Department of Nuclear Medicine, Frankfurt (Germany); Mack, Martin; Vogl, Thomas J. [JW Goethe University, Department of Radiology, Frankfurt (Germany); Bisdas, Sotirios [Eberhard Karls University, Department of Neuroradiology, Tuebingen (Germany)

    2009-10-15

    The purpose of this paper is to evaluate the impact of adding combined {sup 18}F-PET/CT to MRI for T and N staging of the oral and oropharyngeal cancer and calculation of the gross tumor volume (GTV) having histopathology as reference standard. PET/CT and MRI were performed in 66 patients with suspected oral and oropharyngeal cancer (41 primary tumors/25 recurrent tumors) and nodal disease (114 nodes). Statistical analysis included the McNemar test, sensitivity, specificity for the diagnostic modalities as well as regression analysis, and Bland-Altman graphs for calculated tumor volumes. There was no statistically significant difference between the two modalities compared to pathological findings regarding detection of disease (P{>=}0.72). The sensitivity/specificity for tumor detection were 100/80% and 96.72/60% for MRI and PET/CT, respectively. The sensitivity/specificity for nodal metastases were 88.46/75% and 83.81/73.91% for MRI and PET/CT, respectively. In 18% of cases, the MRI-based T staging resulted in an overestimation of the pathologic tumor stage. The corresponding rate for PET/CT was 22%. Regarding the treated necks, both modalities showed 100% sensitivity for detection of the recurrent lesions. In necks with histologically N0 staging, MRI and PET/CT gave 22% and 26% false positive findings, respectively. The mean tumor volume in the pathologic specimen was 16.6{+-}18.6 ml, the mean volume derived by the MR imaging was 17.6{+-}19.1 ml while the estimated by PET/CT volume was 18.8{+-}18.1 ml (P{<=}0.007 between the three methods). The Bland-Altman analysis showed a better agreement between PET/CT and MRI. The diagnostic performance of FDG-PET/CT in the local staging of oral cancer is not superior to MRI. (orig.)

  1. 18F-fluorodeoxyglucose-PET/CT to evaluate tumor, nodal disease, and gross tumor volume of oropharyngeal and oral cavity cancer: comparison with MR imaging and validation with surgical specimen

    International Nuclear Information System (INIS)

    Seitz, Oliver; Chambron-Pinho, Nicole; Sader, Rober; Middendorp, Markus; Mack, Martin; Vogl, Thomas J.; Bisdas, Sotirios

    2009-01-01

    The purpose of this paper is to evaluate the impact of adding combined 18 F-PET/CT to MRI for T and N staging of the oral and oropharyngeal cancer and calculation of the gross tumor volume (GTV) having histopathology as reference standard. PET/CT and MRI were performed in 66 patients with suspected oral and oropharyngeal cancer (41 primary tumors/25 recurrent tumors) and nodal disease (114 nodes). Statistical analysis included the McNemar test, sensitivity, specificity for the diagnostic modalities as well as regression analysis, and Bland-Altman graphs for calculated tumor volumes. There was no statistically significant difference between the two modalities compared to pathological findings regarding detection of disease (P≥0.72). The sensitivity/specificity for tumor detection were 100/80% and 96.72/60% for MRI and PET/CT, respectively. The sensitivity/specificity for nodal metastases were 88.46/75% and 83.81/73.91% for MRI and PET/CT, respectively. In 18% of cases, the MRI-based T staging resulted in an overestimation of the pathologic tumor stage. The corresponding rate for PET/CT was 22%. Regarding the treated necks, both modalities showed 100% sensitivity for detection of the recurrent lesions. In necks with histologically N0 staging, MRI and PET/CT gave 22% and 26% false positive findings, respectively. The mean tumor volume in the pathologic specimen was 16.6±18.6 ml, the mean volume derived by the MR imaging was 17.6±19.1 ml while the estimated by PET/CT volume was 18.8±18.1 ml (P≤0.007 between the three methods). The Bland-Altman analysis showed a better agreement between PET/CT and MRI. The diagnostic performance of FDG-PET/CT in the local staging of oral cancer is not superior to MRI. (orig.)

  2. 46 CFR 57.06-4 - Production testing specimen requirements.

    Science.gov (United States)

    2010-10-01

    ... WELDING AND BRAZING Production Tests § 57.06-4 Production testing specimen requirements. (a) For test... 46 Shipping 2 2010-10-01 2010-10-01 false Production testing specimen requirements. 57.06-4... to welding shall not throw the finished test plate out of line by an angle of over 5°. (c) Where the...

  3. X-ray radiography of Ti6Al4V welded by plasma tungsten arc (PTA) welding

    Energy Technology Data Exchange (ETDEWEB)

    Dikbas, Halil; Caligulu, Ugur; Taskin, Mustafa; Turkmen, Mustafa [Firat Univ., Elazig (Turkey). Metallurgy Dept.

    2013-03-01

    In this study, X-ray radiographic tests of Ti6Al4V alloys welded by plasma tungsten arc welding (PTA) were investigated. PTA welding experiments were carried out under argon shielding gas atmosphere, at 1400-1600 W and 1800 W welding powers as well as 1 m/min, 0.75 m/min, and 0.50 m/min welding speeds. After this process, radiography of the welded joints was performed by X-ray diffraction. The result of the radiographic tests indicated that by increasing welding power the widths of deep penetration increased in all specimens. On the contrary, increasing welding speeds decreases the widths deep penetration. The best properties of Ti6Al4V joints were observed for specimens welded at 1800 W welding power and at 0.50 m/min welding speed. (orig.)

  4. Welding hazards

    International Nuclear Information System (INIS)

    Khan, M.A.

    1992-01-01

    Welding technology is advancing rapidly in the developed countries and has converted into a science. Welding involving the use of electricity include resistance welding. Welding shops are opened in residential area, which was causing safety hazards, particularly the teenagers and children who eagerly see the welding arc with their naked eyes. There are radiation hazards from ultra violet rays which irritate the skin, eye irritation. Welding arc light of such intensity could damage the eyes. (Orig./A.B.)

  5. TIG-dressing of High Strength Butt Welded Connection. Part 2 : Physical Testing and Modelling

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2014-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging

  6. TIG-dressing of high strength butt welded connection - Part 2: physical testing and modelling

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.

    2013-01-01

    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging

  7. Fatigue Behavior of Inconel 718 TIG Welds

    Science.gov (United States)

    Alexopoulos, Nikolaos D.; Argyriou, Nikolaos; Stergiou, Vasillis; Kourkoulis, Stavros K.

    2014-08-01

    Mechanical behavior of reference and TIG-welded Inconel 718 specimens was examined in the present work. Tensile, constant amplitude fatigue, and fracture toughness tests were performed in ambient temperature for both, reference and welded specimens. Microstructure revealed the presence of coarse and fine-grained heat-affected zones. It has been shown that without any post-weld heat treatment, welded specimens maintained their tensile strength properties while their ductility decreased by more than 40%. It was found that the welded specimens had lower fatigue life and this decrease was a function of the applied fatigue maximum stress. A 30% fatigue life decrease was noticed in the high cycle fatigue regime for the welded specimens while this decrease exceeded 50% in the low cycle fatigue regime. Cyclic stress-strain curves showed that Inconel 718 experiences a short period of hardening followed by softening for all fatigue lives. Cyclic fatigue response of welded specimens' exhibited cyclically stable behavior. Finally, a marginal decrease was noticed in the Mode I fracture toughness of the welded specimens.

  8. Remote-welding technique for assembling in-pile IASCC capsule in hot cell

    International Nuclear Information System (INIS)

    Kawamata, Kazuo; Ishii, Toshimitsu; Kanazawa, Yoshiharu; Iwamatsu, Shigemi; Ohmi, Masao; Shimizu, Michio; Matsui, Yoshinori; Saito, Jun-ichi; Ugachi, Hirokazu; Kaji, Yoshiyuki; Tsukada, Takashi

    2006-01-01

    In order to investigate behavior of the irradiation assisted stress corrosion cracking (IASCC) caused by the simultaneous effects of neutron irradiation and high temperature water environment in such a light water reactor (LWR), it is necessary to perform crack growth tests in an in-pile IASCC capsule irradiated in the Japan Materials Testing Reactor (JMTR). The development of the remote-welding technique is essential for remotely assembling the in-pile IASCC capsule installing the pre-irradiated CT specimens. This report describes a new remote-welding machine developed for assembling the in-pile IASCC capsule. The remote-welding technique that the capsule tube is rotated light under the fixed torch was applied to the machine for the welding of thick and large-diameter tubes. The assembly work of four in-pile IASCC capsules having pre-irradiated CT specimens in the hot cell was succeeded for performing the crack growth test under the neutron irradiation in JMTR. The irradiation test of two capsules has been already finished in JMTR without problems. (author)

  9. Fundamental Laser Welding Process Investigations

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1998-01-01

    In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...... video pictures (400 Hz), a clear impact on the seam characteristics has been identified when a hump occurs.Finally, a clear correlation between the position of the focus point, the resultant process type and the corresponding signal intensity and signal variation has been found for sheets welded...

  10. Effects of heat input on the pitting resistance of Inconel 625 welds by overlay welding

    Science.gov (United States)

    Kim, Jun Seok; Park, Young IL; Lee, Hae Woo

    2015-03-01

    The objective of this study was to establish the relationship between the dilution ratio of the weld zone and pitting resistance depending on the heat input to welding of the Inconel alloy. Each specimen was produced by electroslag welding using Inconel 625 as the filler metal. In the weld zone of each specimen, dendrite grains were observed near the fusion line and equiaxed grains were observed on the surface. It was also observed that a melted zone with a high Fe content was formed around the fusion line, which became wider as the welding heat input increased. In order to evaluate the pitting resistance, potentiodynamic polarization tests and CPT tests were conducted. The results of these tests confirmed that there is no difference between the pitting resistances of each specimen, as the structures of the surfaces were identical despite the effect of the differences in the welding heat input for each specimen and the minor dilution effect on the surface.

  11. Welding Curriculum.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

  12. Modelling of microstructural creep damage in welded joints of 316L stainless steel; Modelisation de l'endommagement a haute temperature dans le metal d'apport des joints soudes d'acier inoxydable austenitique

    Energy Technology Data Exchange (ETDEWEB)

    Bouche, G

    2000-07-01

    Welded joints of 316L stainless steel under service conditions at elevated temperature are known to be preferential sites of creep damage, as compared to the base material. This damage results in the formation of cavities and the development of creep cracks which can lead to a premature failure of welded components. The complex two-phase microstructure of 316L welds was simulated by manually filling a mould with longitudinal deposited weld beads. The moulded material was then aged during 2000 hours at 600 deg. C. High resolution Scanning Electron Microscopy was largely used to examine the microstructure of the simulated material before and after ageing. Smooth and notched creep specimens were cut from the mould and tested at 600 deg. C under various stress levels. A comparison of the lifetime versus nominal stress curves for the base and welded materials shows a greater dependence of the welded material to creep phenomena. Observation and EBSD analysis show that damage is preferentially located along the austenite grain boundaries. The stress and strain fields in the notched specimens were calculated by finite element method. A correlation of this field to the observed damage was made in order to propose a predictive law relating the creep damage to the mechanical conditions applied locally. Further mechanical tests and simulation on CT specimens and mode II tubular specimens allowed validating the model under various multiaxial loading conditions. (author)

  13. Wide Panel Testing Technique for Evaluating Repair Weld Strengths

    Science.gov (United States)

    Rogers, Patrick R.; Bynum, Julian E.; Shah, Sandeep R.

    1998-01-01

    This paper describes a new tensile testing technique for evaluating the overall effect of a repair weld on the strength of a welded joint. Previously, repair weld strengths have been evaluated using one-inch width tensile specimens, but this technique does not capture all of the effects that result from a repair. The new technique involves testing of "wide panel" tensile specimens which contain the full length of a repair weld within a longer initial weld, allowing the specimen to capture the combined effects of residual stresses, local strength degradation, and load redistribution around a repair. The development of strains in the repair area of standard aluminum alloy specimens and new high-performance aluminum-lithium alloy specimens was observed and evaluated using photoelastic material. The results of this evaluation show an increased sensitivity to repair welding residual stresses in the aluminum-lithium alloy specimens.

  14. Laser Welding Test Results with Gas Atmospheres in Welding Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

  15. Ultrasonic testing of austenitic welds and its dependency on the welding process

    International Nuclear Information System (INIS)

    Tabatabaeipour, S.M.; Honarvar, F.

    2009-01-01

    This paper describes the ultrasonic testing of austenitic welds prepared by two different welding processes. The tests were carried out by the ultrasonic Time-of-Flight Diffraction (ToFD) technique. Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) are the welding processes used for preparing the specimens. Identical artificial defects were implanted in both welds during the welding process. Both specimens were examined by the ToFD technique under similar conditions. Metallographic images were also obtained from the cross sectional plane of both the SMA and GTA welds. These images show that the grain orientation in the two welded specimens are different. D-scan images obtained by the ToFD technique from these welds indicates that inspecting the specimens prepared by the SMAW process is easier than the one made by the GTAW process. The results also show that the D-scan images cannot reveal the small vertical drilled holes implanted in the specimens. (author)

  16. Effect of CT Specimen Thickness on the Mechanical Characteristics at the Crack Tip of Stress Corrosion Cracking in Ni-based Alloys

    Science.gov (United States)

    Yinghao, Cui; He, Xue; Lingyan, Zhao

    2017-12-01

    It’s important to obtain accurate stress corrosion crack(SCC) growth rate for quantitative life prediction of components in nuclear power plants. However, the engineering practice shows that the crack tip constraint effect has a great influence on the mechanical properties and crack growth rate of SCC at crack tip. To study the influence of the specimen thickness on the crack tip mechanical properties of SCC, the stress, strain and C integral at creep crack tip are analyzed under different specimens thickness. Results show that the cracked specimen is less likely to crack due to effect of crack tip constraint. When the thickness ratio B/W is larger than 0.1, the crack tip constraint is almost ineffective. Value of C integral is the largest when B/W is 0.25. Then specimen thickness has little effect on the value of C integral. The effect of specimen thickness on the value of C integral is less significant at higher thickness ratio.

  17. Welding abilities of UFG metals

    Science.gov (United States)

    Morawiński, Łukasz; Chmielewski, Tomasz; Olejnik, Lech; Buffa, Gianluca; Campanella, Davide; Fratini, Livan

    2018-05-01

    Ultrafine Grained (UFG) metals are characterized by an average grain size of welded joints with similar properties to the base of UFG material are crucial for the production of finished engineering components. Conventional welding methods based on local melting of the joined edges cannot be used due to the UFG microstructure degradation caused by the heat occurrence in the heat affected zone. Therefore, the possibility of obtaining UFG materials joints with different shearing plane (SP) positions by means of friction welded processes, which do not exceed the melting temperature during the process, should be investigated. The article focuses on the Linear Friction Welding (LFW) method, which belongs to innovative welding processes based on mixing of the friction-heated material in the solid state. LFW is a welding process used to joint bulk components. In the process, the friction forces work due to the high frequency oscillation and the pressure between the specimens is converted in thermal energy. Character and range of recrystallization can be controlled by changing LFW parameters. Experimental study on the welded UFG 1070 aluminum alloy by means of FLW method, indicates the possibility of reducing the UFG structure degradation in the obtained joint. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency.

  18. Influence of weld structure on cross-weld creep behavior in P23 steel

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D.J.; Degnan, C.C. [E.ON Engineering (United Kingdom); Brett, S.J. [RWE npower (United Kingdom); Buchanan, L.W. [Doosan Babcock (United Kingdom)

    2010-07-01

    A thick section pipe weld in low alloy steel P23 has been characterised by cross-weld creep rupture testing at a range of stresses, together with all-weld-metal and parent material testing, under the auspices of the UK High Temperature Power Plant Forum. The results generally show that the weld metal can be weak when tested in the transverse (cross-weld) orientation, and can fail with limited overall ductility by cracking in the zone of refined weld metal beneath the fusion boundary of the superposed weld bead. However, one specimen showed a much superior performance, which could be understood in terms of its locally more creep resistant weld macrostructure. The implications for P23 performance and weld manufacture are discussed. (orig.)

  19. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

  20. Resistance seam welding

    International Nuclear Information System (INIS)

    Schueler, A.W.

    1977-01-01

    The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

  1. Mechanical properties and microstructure of F-82H welded joints using CO{sub 2} laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Yamanouchi, N.; Shiba, K.

    1996-10-01

    The laser welding of F-82H was successfully conducted. The heat affected zone of the welding, was about 21 mm width. It was quite adequate to make small specimens, such as SS-3 type sheet tensile specimen.

  2. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

    About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

  3. Residual stress measurements in coil, linepipe and girth welded pipe

    International Nuclear Information System (INIS)

    Law, M.; Prask, H.; Luzin, V.; Gnaeupel-Herold, T.

    2006-01-01

    Residual stresses in gas pipelines come from forming operations in producing the coil and pipe, seam welding the pipe, and girth welding pipes together to form a gas pipeline. Welding is used extensively in gas pipelines, the welds are made without post weld heat treatment. The three normal stresses were measured by neutron diffraction for three types of sample: coil, unwelded rings cut from the pipe made from this coil, and girth welded rings cut from linepipe. All three specimens came from three thicknesses of manufacture (5.4, 6.4, and 7.1 mm). The welds are manual metal arc cellulosic electrode welds made in X70 linepipe, these were measured at 5 through-thickness positions at 19 locations (from the center of the weld up to 35 mm away from the weld) with a spatial resolution of 1 mm 3 . The coil and unwelded rings were measured at the same five through-thickness positions

  4. Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

    Science.gov (United States)

    Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

    2004-04-01

    The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

  5. Fracture toughness of stainless steel welds

    International Nuclear Information System (INIS)

    Mills, W.J.

    1985-11-01

    The effects of temperature, composition and weld-process variations on the fracture toughness behavior for Types 308 and 16-8-2 stainless steel (SS) welds were examined using the multiple-specimen J/sub R/-curve procedure. Fracture characteristics were found to be dependent on temperature and weld process but not on filler material. Gas-tungsten-arc (GTA) welds exhibited the highest fracture toughness, a shielded metal-arc (SMA) weld exhibited an intermediate toughness and submerged-arc (SA) welds yielded the lowest toughness. Minimum-expected fracture properties were defined from lower-bound J/sub c/ and tearing modulus values generated here and in previous studies. Fractographic examination revealed that microvoid coalescence was the operative fracture mechanism for all welds. Second phase particles of manganese silicide were found to be detrimental to the ductile fracture behavior because they separated from the matrix during the initial stages of plastic straining. In SA welds, the high density of inclusions resulting from silicon pickup from the flux promoted premature dimple rupture. The weld produced by the SMA process contained substantially less manganese silicide, while GTA welds contained no silicide inclusions. Delta ferrite particles present in all welds were substantially more resistant to local failure than the silicide phase. In welds containing little or no manganese silicide, delta ferrite particles initiated microvoid coalescence but only after extensive plastic straining

  6. Optimization of process parameters in welding of dissimilar steels using robot TIG welding

    Science.gov (United States)

    Navaneeswar Reddy, G.; VenkataRamana, M.

    2018-03-01

    Robot TIG welding is a modern technique used for joining two work pieces with high precision. Design of Experiments is used to conduct experiments by varying weld parameters like current, wire feed and travelling speed. The welding parameters play important role in joining of dissimilar stainless steel SS 304L and SS430. In this work, influences of welding parameter on Robot TIG Welded specimens are investigated using Response Surface Methodology. The Micro Vickers hardness tests of the weldments are measured. The process parameters are optimized to maximize the hardness of the weldments.

  7. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

  8. Statistical aspects of fatigue crack growth life of base metal, weld metal and heat affected zone in FSWed 7075-T651aluminum alloy

    International Nuclear Information System (INIS)

    Sohn, Hye Jeong; Haryadi, Gunawan Dwi; Kim, Seon Jin

    2014-01-01

    The statistical aspects of fatigue crack growth life of base metal (BM), weld metal (WM) and heat affected zone (HAZ) in friction stir welded (FSWed) 7075-T651 aluminum alloy has been studied by Weibull statistical analysis. The fatigue crack growth tests were performed at room temperature on ASTM standard CT specimens under three different constant stress intensity factor range controls. The main objective of this paper is to investigate the effects of statistical aspects of fatigue crack growth life on stress intensity factor ranges and material properties, namely BM, WM and HAZ specimens. In this work, the Weibull distribution was employed to estimate the statistical aspects of fatigue crack growth life. The shape parameter of Weibull distribution for fatigue crack growth life was significantly affected by material properties and the stress intensity factor range. The scale parameter of WM specimen exhibited the lowest value at all stress intensity factor ranges.

  9. Design of Friction Stir Spot Welding Tools by Using a Novel Thermal-Mechanical Approach.

    Science.gov (United States)

    Su, Zheng-Ming; Qiu, Qi-Hong; Lin, Pai-Chen

    2016-08-09

    A simple thermal-mechanical model for friction stir spot welding (FSSW) was developed to obtain similar weld performance for different weld tools. Use of the thermal-mechanical model and a combined approach enabled the design of weld tools for various sizes but similar qualities. Three weld tools for weld radii of 4, 5, and 6 mm were made to join 6061-T6 aluminum sheets. Performance evaluations of the three weld tools compared fracture behavior, microstructure, micro-hardness distribution, and welding temperature of welds in lap-shear specimens. For welds made by the three weld tools under identical processing conditions, failure loads were approximately proportional to tool size. Failure modes, microstructures, and micro-hardness distributions were similar. Welding temperatures correlated with frictional heat generation rate densities. Because the three weld tools sufficiently met all design objectives, the proposed approach is considered a simple and feasible guideline for preliminary tool design.

  10. Improved design bases of welded joints in seawater

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús

    The presented work aims to investigate and establish a precise, thorough and detailed database from series of experimental testing of submerged arc welded, SAW, specimens of various thicknesses typically applied in offshore structures and foundations. Additionally, the testing was performed in two...... environment on fatigue resistance. Furthermore, novelty 25 mm thick steel laser-hybrid welded specimens in the as welded condition were subjected to experimental testing. A fatigue resistance S-Ncurve was established for the laser hybrid welded joints in addition to a more detailed analysis. The laser hybrid...... different environments, i.e. under in-air conditions and in a corrosion environment. Welded structures of all sizes and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has...

  11. Influence of weld discontinuities on strain controlled fatigue behavior of 308 stainless steel weld metal

    International Nuclear Information System (INIS)

    Bhanu Sankara Rao, K.; Valsan, M.; Sandhya, R.; Mannan, S.L.; Rodriguez, P.

    1994-01-01

    Detailed investigations have been performed for assessing the importance of weld discontinuities in strain controlled low cycle fatigue (LCF) behavior of 308 stainless steel (SS) welds. The LCF behavior of 308 SS welds containing defects was compared with that of type 304 SS base material and 308 SS sound weld metal. Weld pads were prepared by shielded metal arc welding process. Porosity and slag inclusions were introduced deliberately into the weld metal by grossly exaggerating the conditions normally causing such defects. Total axial strain controlled LCF tests have been conducted in air at 823 K on type 304 SS base and 308 SS sound weld metal employing strain amplitudes in the range from ±0.25 to ±0.8 percent. A single strain amplitude of ±0.25 percent was used for all the tests conducted on weld samples containing defects. The results indicated that the base material undergoes cyclic hardening whereas sound and defective welds experience cyclic softening. Base metal showed higher fatigue life than sound weld metal at all strain amplitudes. The presence of porosity and slag inclusions in the weld metal led to significant reduction in life. Porosity on the specimen surface has been found to be particularly harmful and caused a reduction in life by a factor of seven relative to sound weld metal

  12. Investigate The Effect Of Welding Parameters On Mechanical Properties During The Welding Of Al-6061 Alloy

    Directory of Open Access Journals (Sweden)

    Rajendra Prasad

    2017-10-01

    Full Text Available Friction welding is a solid state welding technique which is being used in recent times to weld similar as well as dissimilar metals for getting defect free weld. Many combinations like low carbon to stainless steel austenitic to ferrite stainless steel aluminium to copper and titanium to aluminium or steel have been tried out by various solid state welding processes with quite good results. In the present work the 3 level full factorial design has been employed to investigate the effect of welding parameters on tensile strength toughness and heat generation during the welding of Al-6061 alloy. Mathematical relationships between friction welding parameters and mechanical properties like heat generation tensile strength and toughness have also been developed. An attempt has also been made to examine the fracture surfaces of test specimens using SEM. It has been found that welding speed is the most significant parameter thats affect the heat generation tensile strength and toughness. it has been found that tensile strength and toughness during welding increases with increased in welding speed while tensile strength and toughness initially increased as the welding time increases after that it decreased with increase in welding time. The difference in weight of alloying elements can be clearly seen by analyzing spectrum of elements.

  13. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  14. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  15. Development of Reconstitution Technology for Surveillance Specimens

    International Nuclear Information System (INIS)

    Yasushi Atago; Shunichi Hatano; Eiichiro Otsuka

    2002-01-01

    The Japan Power Engineering and Inspection Corporation (JAPEIC) has been carrying out the project titled 'Nuclear Power Plant Integrated Management Technology (PLIM)' consigned by Japanese Ministry of Economy, Trade and Industry (METI) since 1996FY as a 10-years project. As one of the project themes, development of reconstitution technology for reactor pressure vessel (RPV/RV) surveillance specimens, which are installed in RPVs to monitor the neutron irradiation embrittlement on RPV/RV materials, is now on being carried out to deal with the long-term operation of nuclear power plants. The target of this theme is to establish the technical standard for applicability of reconstituted surveillance specimens including the reconstitution of the Charpy specimens and Compact Tension (CT) specimens. With the Charpy specimen reconstitution, application of 10 mm length inserts is used, which enables the conversion of tests from the LT-direction to the TL-direction. This paper presents the basic data from Charpy and CT specimens of RPV materials using the surveillance specimens obtained for un-irradiated materials including the following. 1) Reconstitution Technology of Charpy Specimens. a) The interaction between plastic zone and Heat Affected Zone (HAZ). b) The effects of the possible deviations from the standard specimens for the reconstituted specimens. 2) Reconstitution Technology of CT specimens. a) The correlation between fracture toughness and plastic zone width. Because the project is now in progress, this paper describes the outline of the results obtained as of the end of 2000 FY. (authors)

  16. Welding stresses

    International Nuclear Information System (INIS)

    Poirier, J.; Barbe, B.; Jolly, N.

    1976-01-01

    The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

  17. Simulation of Welding Distortions in Theory and Practice

    DEFF Research Database (Denmark)

    Birk-Sørensen, Martin; Kierkegaard, Henning

    1997-01-01

    by an optimised welding order. Welding test samples prove that the constraint of the sample and the time between each pass in a multipass weld affect the magnitude of distortion. Experiments with welding specimens in the form of butt-and fillet welds have been carried out. They show angular deflections as well......In the last few years the use of robot welding processes has increased significatnly. The programming of the robots has until now mainly focused on high efficiency, i.e.high torch rate time, and hence, minimising the inefficient "travelling" time. Together with developing high-performance welding...... due to cutting and welding and parlty in the form of dimensional variation due to human factors. Measurements have been made of the production line for assemblies. The measurements show that distortions related to the multirobot welding are a factor which can rather easily be controlled...

  18. A study on the fatigue characteristics of SM 490 A material due to the welding type

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hoon; Goo, Byung Choon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2004-07-01

    This study investigates the fatigue characteristics of SM 490 A material specimens for the railway vehicle due to the welding type. The more stress ratio decreases, the more strength of fillet welded specimen decreases. At specially, when the stress ratio of TN(Plate with transverse fillet welded rib) specimens decreases 0.5, 0.1, and -0.1, the fatigue limit decreases uniformly. The strength of TN is higher than it of NCN in the compare of fillet welding type, but the strength of NCN(Non load-carrying cruciform fillet welded joint) is higher than it of CN(Load-carrying cruciform fillet welded joint), which these specimens have the rib in the both side. We analysis the strains on the weld positions of the TN specimens during the fatigue test for the investigation of crack initiation and crack growth. In the theses results, we could find the fatigue crack initiation point and time.

  19. Material property evaluations of bimetallic welds, stainless steel saw fusion lines, and materials affected by dynamic strain aging

    Energy Technology Data Exchange (ETDEWEB)

    Rudland, D.; Scott, P.; Marschall, C.; Wilkowski, G. [Battelle Memorial Institute, Columbus, OH (United States)

    1997-04-01

    Pipe fracture analyses can often reasonably predict the behavior of flawed piping. However, there are material applications with uncertainties in fracture behavior. This paper summarizes work on three such cases. First, the fracture behavior of bimetallic welds are discussed. The purpose of the study was to determine if current fracture analyses can predict the response of pipe with flaws in bimetallic welds. The weld joined sections of A516 Grade 70 carbon steel to F316 stainless steel. The crack was along the carbon steel base metal to Inconel 182 weld metal fusion line. Material properties from tensile and C(T) specimens were used to predict large pipe response. The major conclusion from the work is that fracture behavior of the weld could be evaluated with reasonable accuracy using properties of the carbon steel pipe and conventional J-estimation analyses. However, results may not be generally true for all bimetallic welds. Second, the toughness of austenitic steel submerged-arc weld (SAW) fusion lines is discussed. During large-scale pipe tests with flaws in the center of the SAW, the crack tended to grow into the fusion line. The fracture toughness of the base metal, the SAW, and the fusion line were determined and compared. The major conclusion reached is that although the fusion line had a higher initiation toughness than the weld metal, the fusion-line J-R curve reached a steady-state value while the SAW J-R curve increased. Last, carbon steel fracture experiments containing circumferential flaws with periods of unstable crack jumps during steady ductile tearing are discussed. These instabilities are believed to be due to dynamic strain aging (DSA). The paper discusses DSA, a screening criteria developed to predict DSA, and the ability of the current J-based methodologies to assess the effect of these crack instabilities. The effect of loading rate on the strength and toughness of several different carbon steel pipes at LWR temperatures is also discussed.

  20. WELDING METHOD

    Science.gov (United States)

    Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

    1959-09-29

    A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

  1. Low-cycle fatigue of welded joints of alloy AMg5

    International Nuclear Information System (INIS)

    Modestova, R.V.; Borisenko, V.A.; Parfenova, I.N.; Stepanov, S.V.

    1986-01-01

    The authors study the low-cycle fatigue of welded joints of aluminum alloy AMg5 in order to determine the cyclic strength coefficient of welded seams. Tests were carried out on cylindrical specimens of the parent metal, welded specimens, and models of welded vessels. The average values of mechanical properties of the specimens and the parent metal are shown. It is shown that when designing welded vessels of aluminum alloy AMg5, the permissible amplitudes of conventional compressive stresses are recommended to be determined as the lower of the two values calculated using the equations presented

  2. Mechanical Properties of Welded Deformed Reinforcing Steel Bars

    Directory of Open Access Journals (Sweden)

    Ghafur H. Ahmed

    2015-05-01

    Full Text Available Reinforcement strength, ductility and bendability properties are important components in design of reinforced concrete members, as the strength of any member comes mainly from reinforcement. Strain compatibility and plastic behaviors are mainly depending on reinforcement ductility. In construction practice, often welding of the bars is required. Welding of reinforcement is an instant solution in many cases, whereas welding is not a routine connection process. Welding will cause deficiencies in reinforcement bars, metallurgical changes and re-crystallization of microstructure of particles. Weld metal toughness is extremely sensitive to the welding heat input that decreases both of its strength and ductility. For determining the effects of welding in reinforcement properties, 48 specimens were tested with 5 different bar diameters, divided into six groups. Investigated parameters were: properties of un-welded bars; strength, ductility and density of weld metal; strength and ductility reduction due to heat input for bundled bars and transverse bars; welding effect on bars’ bending properties; behavior of different joint types; properties of three weld groove shapes also the locations and types of failures sections. Results show that, strength and elongation of the welded bars decreased by (10-40% and (30-60% respectively. Cold bending of welded bars and groove welds shall be prevented.

  3. Recent advances on Charpy specimen reconstitution techniques

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Arnaldo H.P.; Lobo, Raquel M.; Miranda, Carlos Alexandre J., E-mail: aandrade@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    Charpy specimen reconstitution is widely used around the world as a tool to enhance or supplement surveillance programs of nuclear reactor pressure vessels. The reconstitution technique consists in the incorporation of a small piece from a previously tested specimen into a compound specimen, allowing to increase the number of tests. This is especially important if the available materials is restricted and fracture mechanics parameter have to be determined. The reconstitution technique must fulfill some demands, among them tests results like the original standard specimens and the loaded material of the insert must not be influenced by the welding and machining procedure. It is known that reconstitution of Charpy specimens may affect the impact energy in a consequence of the constraint of plastic deformation by the hardened weldment and HAZ. This paper reviews some recent advances of the reconstitution technique and its applications. (author)

  4. Recent advances on Charpy specimen reconstitution techniques

    International Nuclear Information System (INIS)

    Andrade, Arnaldo H.P.; Lobo, Raquel M.; Miranda, Carlos Alexandre J.

    2017-01-01

    Charpy specimen reconstitution is widely used around the world as a tool to enhance or supplement surveillance programs of nuclear reactor pressure vessels. The reconstitution technique consists in the incorporation of a small piece from a previously tested specimen into a compound specimen, allowing to increase the number of tests. This is especially important if the available materials is restricted and fracture mechanics parameter have to be determined. The reconstitution technique must fulfill some demands, among them tests results like the original standard specimens and the loaded material of the insert must not be influenced by the welding and machining procedure. It is known that reconstitution of Charpy specimens may affect the impact energy in a consequence of the constraint of plastic deformation by the hardened weldment and HAZ. This paper reviews some recent advances of the reconstitution technique and its applications. (author)

  5. Effect of weld morphology on mechanical response and failure of friction stir welds in a naturally aged aluminium alloy

    International Nuclear Information System (INIS)

    Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

    2013-01-01

    Highlights: ► Friction stir welds of AA 6063-T4 are obtained using three tool pin profiles. ► Signature of weld defects in mechanical response of welds is investigated. ► Correlation between peak temperatures in HAZs and their hardness is studied. ► Reasons for strengthening of WNZ and softening of HAZs are found using TEM and XRD. ► A FEM model for the weld zone is developed and validated. -- Abstract: Friction stir butt welds in 6063-T4 aluminium alloy were obtained using square and two tapered tool pin profiles. Tensile tests at 0°, 45°, and 90° to the weld line, hardness contours in the weld cross-section, temperatures in the heat affected zones, cross-sectional macrographs, transmission electron micrographs, and X-ray diffraction studies were used to characterize the welds. In transverse weld specimen, tunnel defects appearing at higher weld speeds for tapered pin profiles, were found to result in mechanical instabilities, i.e. sharp drops in load–displacement curves, much before macroscopic necking occured. Further, in comparison to the base metal, a marked reduction in ductility was observed even in transverse specimen with defect free welds. Hardness contours in the weld cross-section suggest that loss in ductility is due to significant softening in heat affected zone on the retreating side. Transmission electron microscopy images demonstrate that while recovery and overaging are responsible for softening in the heat affected zone, grain size refinement from dynamic recrystallization is responsible for strengthening of the weld nugget zone. X-ray diffraction studies in the three weld zones: weld nugget zone, heat affected zone, and the base metal corroborate these findings. A weld zone model, for use in forming simulations on friction stir welded plates of naturally aged aluminium alloys, was proposed based on mechanical characterization tests. The model was validated using finite element analysis.

  6. Thermal analysis of laser welding for ITER correction coil case

    Energy Technology Data Exchange (ETDEWEB)

    Fang, C., E-mail: fangchao@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 200031 (China); Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland); Song, Y.T.; Wu, W.Y.; Wei, J.; Xin, J.J. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 200031 (China); Wu, H.P.; Salminen, A. [Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland)

    2015-11-15

    Highlights: • Morphology of simulated heat source is found to be close to the welded joint sample. • The FEA temperature distribution shows good agreement with experimental measurements. • Laser welding process used on ITER correction coil case will not harm the winding pack. - Abstract: This paper presents the simulation results of 3D finite element analysis (FEA) of laser welding processes for the ITER correction coil case welding; predicts the temperature distribution and compares it with the experimental result to evaluate the impact to the properties of winding pack during the welding process. A specimen of coil case was modeled and simulated by using specialized welding simulation software SYSWELD, Modeling used austenitic stainless steel 316LN as the specimen material and a 3D Conical Gaussian was used as a heat source model. A plate sample was welded before the FE modeling in order to obtain the laser welding parameters and the Gaussian parameters of molten pool. To verify the simulation results, a coil case sample was welded using laser welding with welding parameters that matched the model, and the corresponding temperature values were measured using thermocouples. Compared with the FEA results, it was found that the FEA temperature distribution shows good agreement with the experimental measurements and the laser welding process will not harm the winding pack.

  7. Fatigue crack growth rate studies on pipes and pipe welds made of austenitic stainless steel and carbon steel

    International Nuclear Information System (INIS)

    Arora, Punit; Singh, P.K.; Bhasin, Vivek; Vaze, K.K.; Pukazhendhi, D.M.; Gandhi, P.; Raghava, G.

    2011-01-01

    The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel and carbon steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined for pipe (base) and pipe weld materials by using Compact Tension (CT)/Three Point Bend (TPB) specimens machined from the actual pipe/pipe weld. Analyses have been carried out to predict the fatigue crack growth life of pipes/pipe welds having part through cracks on the outer surface. In the analyses, Stress Intensity Factors (K) have been evaluated through two different schemes. The first scheme considers the 'K' evaluations at two points of the crack front i.e. maximum crack depth and crack tip at the outer surface. The second scheme accounts for the area averaged root mean square stress intensity factor (K RMS ) at deepest and surface points. In order to validate the analytical procedure/results, experiments have been carried out on full scale pipe and pipe welds with part through circumferential crack. Fatigue crack growth life evaluated using both schemes have been compared with experimental results. Use of stress intensity factor (K RMS ) evaluated using second scheme gives better fatigue crack growth life prediction compared to that of first scheme. (author)

  8. Butt Weldability for SS400 Using Laser-Arc Hybrid Welding

    International Nuclear Information System (INIS)

    Kim, Jong Do; Myoung, Gi Hoon; Park, Duck; Myoung, Gi Hoon; Park, In Duck

    2016-01-01

    This study presents results of an experimental investigation of the laser-arc, hybrid, butt welding process of SS400 structural steel. Welding parameters including laser power, welding current and speed were varied in order to obtain one-pass, full-penetration welds without defects. The conditions that resulted in optimal beads were identified. After welding, hardness measurements and microstructure observations were carried out in order to study weld properties. The mechanical properties of both the base material and welded specimen were compared based on the results of tensile strength measurements. The yield and tensile strengths were found to be similar

  9. A study on the fatigue strength characteristics of ship structural steel with gusset welds

    Directory of Open Access Journals (Sweden)

    Sung-Jo Park

    2012-06-01

    Full Text Available This study aims to assess fatigue property by the static overload and average load in the fillet welded joints which is on the ship structural steel having gusset welds. To this end, a small specimen was made, to which the same welding condition for the actual ship structure was applied, to perform fatigue tests. In this study, a method to simply assess changes in welding residual stress according to different static overload was suggested. By measuring actual strain at the weld toe, the weld stress concentration factor and property which is determined by recrystallization in the process of welding were estimated to investigate the relation between overload and fatigue strength.

  10. Butt Weldability for SS400 Using Laser-Arc Hybrid Welding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Do; Myoung, Gi Hoon; Park, Duck [Korea Maritime and Ocean Univ., Busan (Korea, Republic of); Myoung, Gi Hoon; Park, In Duck [Korea Institute of Machinery and Materials, Busan (Korea, Republic of)

    2016-07-15

    This study presents results of an experimental investigation of the laser-arc, hybrid, butt welding process of SS400 structural steel. Welding parameters including laser power, welding current and speed were varied in order to obtain one-pass, full-penetration welds without defects. The conditions that resulted in optimal beads were identified. After welding, hardness measurements and microstructure observations were carried out in order to study weld properties. The mechanical properties of both the base material and welded specimen were compared based on the results of tensile strength measurements. The yield and tensile strengths were found to be similar.

  11. Welding of zircalloy-2 and zircalloy-4 by CO2 laser and by TIG

    International Nuclear Information System (INIS)

    Ram, V.

    1990-01-01

    This study deals with the welding of zircaloy-2 and zircaloy-4 by means of two techniqes, namely tungsten inert gas welding and CO 2 laser welding. Suitable devices and jigs were developed and manufactured to allow the welding of flat specimens and cylindrical specimens. The optimal welding parameters for the two welding methods were determined. The quality of the welds was determined by tensile strength tests at room temperature and by determining the corrosion resistance to steam at temprature of 450 deg C, 550 deg C, and at 650 deg C. The influence of the weld on the microstructure of the material, on its composition and its crystallographic structure was investigated. Analysis of fracture surfaces of the tensile specimens was carried out with a scanning electron microscope. (author)

  12. Welding process

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    For the final chapter of this book, there is basic introduction on welding process. The good radiography must know somehow on welding process so that they can know what kind of welding that must rejected or not. All of the exposure technique that mention in earlier chapter almost applicable in this field because welding process is critical problem if there is no inspection will be done. So, for this chapter, all the discontinuity that usually appeared will be discussed and there is another discontinuity maybe not to important and do not give big impact if found it, do not described here. On top of that, the decision to accept or reject based on code, standard and specification that agreed by both to make sure that decision that agreed is corrected and more meaningful.

  13. Tensile strength of laser welded cobalt-chromium alloy with and without an argon atmosphere.

    Science.gov (United States)

    Tartari, Anna; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

    2010-06-01

    The tensile strength and depth of weld of two cobalt chromium alloys before and after laser welding with and without an argon gas atmosphere were investigated. Using two cobalt chromium alloys, rod shaped specimens (5 cm x 1.5 mm) were cast. Specimens were sand blasted, sectioned and welded with a pulsed Nd: YAG laser welding machine and tested in tension using an Instron universal testing machine. A statistically significant difference in tensile strength was observed between the two alloys. The tensile strength of specimens following laser welding was significantly less than the unwelded controls. Scanning electron microscopy showed that the micro-structure of the cast alloy was altered in the region of the weld. No statistically significant difference was found between specimens welded with or without an argon atmosphere.

  14. Syllabus in Trade Welding.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

  15. Structural integrity and fatigue crack propagation life assessment of welded and weld-repaired structures

    Science.gov (United States)

    Alam, Mohammad Shah

    2005-11-01

    Structural integrity is the science and technology of the margin between safety and disaster. Proper evaluation of the structural integrity and fatigue life of any structure (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) is important to ensure the public safety, environmental protection, and economical consideration. Catastrophic failure of any structure can be avoided if structural integrity is assessed and necessary precaution is taken appropriately. Structural integrity includes tasks in many areas, such as structural analysis, failure analysis, nondestructive testing, corrosion, fatigue and creep analysis, metallurgy and materials, fracture mechanics, fatigue life assessment, welding metallurgy, development of repairing technologies, structural monitoring and instrumentation etc. In this research fatigue life assessment of welded and weld-repaired joints is studied both in numerically and experimentally. A new approach for the simulation of fatigue crack growth in two elastic materials has been developed and specifically, the concept has been applied to butt-welded joint in a straight plate and in tubular joints. In the proposed method, the formation of new surface is represented by an interface element based on the interface potential energy. This method overcomes the limitation of crack growth at an artificial rate of one element length per cycle. In this method the crack propagates only when the applied load reaches the critical bonding strength. The predicted results compares well with experimental results. The Gas Metal Arc welding processes has been simulated to predict post-weld distortion, residual stresses and development of restraining forces in a butt-welded joint. The effect of welding defects and bi-axial interaction of a circular porosity and a solidification crack on fatigue crack propagation life of butt-welded joints has also been investigated. After a weld has been repaired, the specimen was tested in a universal

  16. Laser welding of Ti-Ni type shape memory alloy

    International Nuclear Information System (INIS)

    Hirose, Akio; Araki, Takao; Uchihara, Masato; Honda, Keizoh; Kondoh, Mitsuaki.

    1990-01-01

    The present study was undertaken to apply the laser welding to the joining of a shape memory alloy. Butt welding of a Ti-Ni type shape memory alloy was performed using 10 kW CO 2 laser. The laser welded specimens showed successfully the shape memory effect and super elasticity. These properties were approximately identical with those of the base metal. The change in super elasticity of the welded specimen during tension cycling was investigated. Significant changes in stress-strain curves and residual strain were not observed in the laser welded specimen after the 50-time cyclic test. The weld metal exhibited the celler dendrite. It was revealed by electron diffraction analysis that the phase of the weld metal was the TiNi phase of B2 structure which is the same as the parent phase of base metal and oxide inclusions crystallized at the dendrite boundary. However, oxygen contamination in the weld metal by laser welding did not occur because there was almost no difference in oxygen content between the base metal and the weld metal. The transformation temperatures of the weld metal were almost the same as those of the base metal. From these results, laser welding is applicable to the joining of the Ti-Ni type shape memory alloy. As the application of laser welding to new shape memory devices, the multiplex shape memory device of welded Ti-50.5 at % Ni and Ti-51.0 at % Ni was produced. The device showed two-stage shape memory effects due to the difference in transformation temperature between the two shape memory alloys. (author)

  17. Examination of weld defects by computed tomography

    Directory of Open Access Journals (Sweden)

    M. Jovanović

    2012-04-01

    Full Text Available Defects in metal arc gas (MAG welds made in S235JR low carbon steel of 6 mm thickness were examined. A sample containing lack of fusion (LOF and pores was examined by computed tomography – CT. The computed tomography examination was performed in order to define LOF size and position as well as dimensions and distribution of accompanying pores in the weld metal.

  18. Effect of rotation speed and welding speed on Friction Stir Welding of AA1100 Aluminium alloy

    Science.gov (United States)

    Raja, P.; Bojanampati, S.; Karthikeyan, R.; Ganithi, R.

    2018-04-01

    Aluminum AA1100 is the most widely used grade of Aluminium due to its excellent corrosion resistance, high ductility and reflective finish, the selected material was welded with Friction Stir Welding (FSW) process on a CNC machine, using a combination of different tool rotation speed (1500 rpm, 2500 rpm, 3500 rpm) and welding speed (10 mm/min, 30 mm/min, 50 mm/min) as welding parameters. The effect of FSW using this welding parameter was studied by measuring the ultimate tensile strength of the welded joints. A high-speed steel tool was prepared for welding the Aluminium AA1100 alloy having an 8mm shoulder diameter and pin dimension of 4mm diameter and 2.8 mm length. The welded joints were tested using the universal testing machine. It was found that Ultimate Tensile Strength of FSW specimen was highest with a value of 98.08 MPa when the weld was performed at rotation speed of 1500 RPM and welding speed of 50 mm/min.

  19. Microstructure and mechanical properties in TIG welding of CLAM steel

    International Nuclear Information System (INIS)

    Zhu Qiang; Lei Yucheng; Chen Xizhang; Ren Wenjie; Ju Xin; Ye Yimin

    2011-01-01

    Tungsten insert gas (TIG) welding on China low activation martensitic (CLAM) steel under identical conditions was performed. Microhardness test, tensile test, Charpy impact test and microstructure measurements were carried out on TIG welded joints after post weld heat-treatment. Hardening at WM and softening in HAZ is detected in the TIG weld joint. Microhardness in WM decreased when the temperature of PWHT increased. The ultimate tensile stress of weld metal is higher than that of HAZ and BM. Absorbed energy increased with PWHT temperature rising, until PWHT was done at 760 deg. C/30 min, the specimen ductile fractured in local area. The microstructure of the weld metal for every specimen was found to be tempered martensite with a little of delta ferrite. M 23 C 6 particles are the predominant type of carbides. Oxide precipitate phases appeared in WM, which are the primary crack initiation sites and it is critically important minimize their formation.

  20. Urine culture - catheterized specimen

    Science.gov (United States)

    Culture - urine - catheterized specimen; Urine culture - catheterization; Catheterized urine specimen culture ... urinary tract infections may be found in the culture. This is called a contaminant. You may not ...

  1. Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Braun, R.; Dalle Donne, C.; Staniek, G.

    2000-01-01

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β '' (Mg 2 Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  2. Creep testing and creep loading experiments on friction stir welds in copper at 75 deg C

    International Nuclear Information System (INIS)

    Andersson, Henrik C.M.; Seitisleam, Facredin; Sandstroem, Rolf

    2007-08-01

    Specimens cut from friction stir welds in copper canisters for nuclear waste have been used for creep experiments at 75 deg C. The specimens were taken from a cross-weld position as well as heat affected zone and weld metal. The parent metal specimens exhibited longer creep lives than the weld specimens by a factor of three in time. They in turn were longer than those for the crossweld and HAZ specimens by an order of magnitude. The creep exponent was in the interval 50 to 69 implying that the material was well inside the power-law breakdown regime. The ductility properties expressed as reduction in area were not significantly different and all the rupture specimens demonstrated values exceeding 80%. Experiments were also carried out on the loading procedure of a creep test. Similar parent metal specimens and test conditions were used and the results show that the loading method has a large influence on the strain response of the specimen

  3. Creep testing and creep loading experiments on friction stir welds in copper at 75 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Henrik C.M.; Seitisleam, Facredin; Sandstroem, Rolf [Corrosion an d Metals Research Institute, Stockholm (Sweden)

    2007-08-15

    Specimens cut from friction stir welds in copper canisters for nuclear waste have been used for creep experiments at 75 deg C. The specimens were taken from a cross-weld position as well as heat affected zone and weld metal. The parent metal specimens exhibited longer creep lives than the weld specimens by a factor of three in time. They in turn were longer than those for the crossweld and HAZ specimens by an order of magnitude. The creep exponent was in the interval 50 to 69 implying that the material was well inside the power-law breakdown regime. The ductility properties expressed as reduction in area were not significantly different and all the rupture specimens demonstrated values exceeding 80%. Experiments were also carried out on the loading procedure of a creep test. Similar parent metal specimens and test conditions were used and the results show that the loading method has a large influence on the strain response of the specimen.

  4. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  5. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    Chiu, Liu Ho; Hsieh, Wen Chin

    2003-01-01

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ 2 and Cr 2 N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl 3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  6. Welding template

    International Nuclear Information System (INIS)

    Ben Venue, R.J. of.

    1976-01-01

    A welding template is described which is used to weld strip material into a cellular grid structure for the accommodation of fuel elements in a nuclear reactor. On a base plate the template carries a multitude of cylindrical pins whose upper half is narrower than the bottom half and only one of which is attached to the base plate. The others are arrested in a hexagonal array by oblong webs clamped together by chuck jaws which can be secured by means of screws. The parts are ground very accurately. The template according to the invention is very easy to make. (UWI) [de

  7. Corrosion behaviour of welds and Ta in liquid lead

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, A., E-mail: Annette.heinzel@kit.edu; Müller, G.; Weisenburger, A.

    2016-02-15

    Four specimens, P91 welded by friction stir welding with and without post heat treatment, P91 electromagnetic pulse welded (EMP) and 14Cr ODS (explosive welding) were exposed at 550 °C for up to 2131 h to Pb containing 10{sup −6} wt% oxygen. After the exposure none of the samples showed dissolution attack, all were protected by an oxide layer at the surface. Nearly no effect on the oxidation due to welding was found in both friction stir welded specimens. Severe deformation and partial melting during explosive welding result in a slower oxide layer growth within the welding zone. The EMP sample was tested as delivered without post-heat treatment. No Pb penetrated into the tiny gap between the welded parts. After the test, the gap is filled up with oxides. Additionally, Ta, discussed as a pump impeller material, was exposed to Pb and PbBi at different temperatures (400–900 °C) and oxygen concentrations in liquid metal (saturated, 10{sup −6} wt%, 10{sup −8} wt% and reduced (<<10{sup −8} wt%). Only the Ta specimens exposed to Pb with highly reduced oxygen content showed nearly no attack. All the others exhibited oxide scale formation that becomes severe above 400 °C test temperature.

  8. High Temperature Fatigue Crack Growth Rate Studies in Stainless Steel 316L(N Welds Processed by A-TIG and MP-TIG Welding.

    Directory of Open Access Journals (Sweden)

    Thomas Manuel

    2018-01-01

    Full Text Available Welded stainless steel components used in power plants and chemical industries are subjected to mechanical load cycles at elevated temperatures which result in early fatigue failures. The presence of weld makes the component to be liable to failure in view of residual stresses at the weld region or in the neighboring heat affected zone apart from weld defects. Austenitic stainless steels are often welded using Tungsten Inert Gas (TIG process. In case of single pass welding, there is a reduced weld penetration which results in a low depth-to-width ratio of weld bead. If the number of passes is increased (Multi-Pass TIG welding, it results in weld distortion and subsequent residual stress generation. The activated flux TIG welding, a variant of TIG welding developed by E.O. Paton Institute, is found to reduce the limitation of conventional TIG welding, resulting in a higher depth of penetration using a single pass, reduced weld distortion and higher welding speeds. This paper presents the fatigue crack growth rate characteristics at 823 K temperature in type 316LN stainless steel plates joined by conventional multi-pass TIG (MP-TIG and Activated TIG (A-TIG welding process. Fatigue tests were conducted to characterize the crack growth rates of base metal, HAZ and Weld Metal for A-TIG and MP-TIG configurations. Micro structural evaluation of 316LN base metal suggests a primary austenite phase, whereas, A-TIG weld joints show an equiaxed grain distribution along the weld center and complete penetration during welding (Fig. 1. MP-TIG microstructure shows a highly inhomogeneous microstructure, with grain orientation changing along the interface of each pass. This results in tortuous crack growth in case of MP-TIG welded specimens. Scanning electron microscopy studies have helped to better understand the fatigue crack propagation modes during high temperature testing.

  9. Optimization of weld bead geometry of MS plate

    Indian Academy of Sciences (India)

    The considered specimen was checked to harmonize the optimum setting between input factors, for example, welding current, open circuit voltage, and thickness of plate, with respect to obtaining prosperous weld strength as well as bead geometry quality characteristics, for example, tensile strength, bead width, ...

  10. Optimization of the A-TIG welding for stainless steels

    Science.gov (United States)

    Jurica, M.; Kožuh, Z.; Garašić, I.; Bušić, M.

    2018-03-01

    The paper presents the influence of the activation flux and shielding gas on tungsten inert gas (A-TIG) welding of the stainless steel. In introduction part, duplex stainless steel was analysed. The A-TIG process was explained and the possibility of welding stainless steels using the A-TIG process to maximize productivity and the cost-effectiveness of welded structures was presented. In the experimental part duplex, 7 mm thick stainless steel has been welded in butt joint. The influence of activation flux chemical composition upon the weld penetration has been investigated prior the welding. The welding process was performed by a robot with TIG equipment. With selected A-TIG welding technology preparation of plates and consumption of filler material (containing Cr, Ni and Mn) have been avoided. Specimens sectioned from the produced welds have been subjected to tensile strength test, macrostructure analysis and corrosion resistance analysis. The results have confirmed that this type of stainless steel can be welded without edge preparation and addition of filler material containing critical raw materials as Cr, Ni and Mn when the following welding parameters are set: current 200 A, welding speed 9,1 cm/min, heat input 1,2 kJ/mm and specific activation flux is used.

  11. Experimental Investigation on Electric Current-Aided Laser Stake Welding of Aluminum Alloy T-Joints

    Directory of Open Access Journals (Sweden)

    Xinge Zhang

    2017-11-01

    Full Text Available In the present study, aluminum alloy T-joints were welded using the laser stake-welding process. In order to improve the welding quality of the T-joints, an external electric current was used to aid the laser stake-welding process. The effects of the process parameters on the weld morphology, mechanical properties, and microstructure of the welded joints were analyzed and discussed in detail. The results indicate that the aided electric current should be no greater than a certain maximum value. Upon increasing the aided electric current, the weld width at the skin and stringer faying surface obviously increased, but there was an insignificant change in the penetration depth. Furthermore, the electric current and pressing force should be chosen to produce an expected weld width at the faying surface, whereas the laser power and welding speed should be primarily considered to obtain an optimal penetration depth. The tensile shear specimens failed across the faying surface or failed in the weld zone of the skin. The specimens that failed in the weld of the skin could resist a higher tensile shear load compared with specimens that failed across the faying surface. The microstructural observations and microhardness results demonstrated that the tensile shear load capacity of the aluminum alloy welded T-joint was mainly determined by the weld width at the faying surface.

  12. Electron beam welding of dissimilar metals

    International Nuclear Information System (INIS)

    Metzger, G.; Lison, R.

    1976-01-01

    Thirty-three two-memeber combinations of dissimilar metals were electron beam welded as square-groove butt joints in 0.08 and 0.12 in. sheet material. Many joints were ''braze welded'' by offsetting the electron beam about 0.02 in. from the butt joint to achieve fusion of the lower melting point metal, but no significant fusion of the other member of the pair. The welds were evaluated by visual and metallographic examination, transverse tensile tests, and bend tests. The welds Ag/Al, Ag/Ni15Cr7Fe, Cu/Ni15Cr7Fe, Cu/V, Cu20Ni/Ni15Cr7Fe, Fe18Cr8Ni/Ni, Fe18Cr8Ni/Ni15Cr7Fe, Nb/Ti, Nb/V, Ni/Ni15Cr7Fe, and Cb/V10Ti were readily welded and weld properties were excellent. Others which had only minor defects included the Ag/Cu20Ni, Ag/Ti, Ag/V, Cu/Fe18Cr8Ni, Cu/V10Ti, Cu20Ni/Fe18Cr8Ni, and Ti/Zr2Sn welds. The Cu/Ni weld had deep undercut, but was in other respects excellent. The mechanical properties of the Ag/Fe18Cr8Ni weld were poor, but the defect could probably be corrected. Difficulty with cracking was experienced with the Al/Ni and Fe18Cr8Ni/V welds, but sound welds had excellent mechanical properties. The remaining welds Al-Cu, Al/Cu20Ni, Al/Fe18Cr8Ni, Al/Ni15Cr7Fe, Cu20Ni/V, Cu20Ni/V10Ti, Cb/Zr2Sn, Ni/Ti, Ni15Cr7Fe/V, Ni15Cr7Fe/V10Ti, and Ti/V were unsuccessful, due to brittle phases, primarily at the weld metal-base metal interface. In addition to the two-member specimens, several joints were made by buttering. Longitudinal weld specimens of the three-member combination Al/Ni/Fe18Cr8Ni and the five member combination Fe18Cr8Ni/V/Cb/Ti/Zr2Sn showed good tensile strength and satisfactory elongation. 6 tables, 16 figures

  13. Fatigue strength of socket welded pipe joint

    International Nuclear Information System (INIS)

    Iida, K.; Matsuda, F.; Sato, M.; Higuchi, M.; Nakagawa, A.

    1994-01-01

    Fully reversed four point bending fatigue tests were carried out of small diameter socket welded joints made of carbon steels. Experimental parameters are pipe diameter, thickness of pipe and socket wall, throat depth and shape of fillet welds, slip-on and diametral gaps in the socket welding, lack of penetration at the root of fillet welds, and peening of fillet welds. In most cases a fatigue crack started from the root of the fillet, but in the case of higher stress amplitude, it tended to start from the toe of fillet. The standard socket welded joint of 50 mm diameter showed relatively low fatigue strength, 46 MPa in stress amplitude at the 10 7 cycles failure life. This value corresponds to about 1/5 of that of the smoothed base metal specimens in axial fatigue. The fatigue strength showed decrease with increasing pipe diameter, and increase with increasing the thickness of pipe and socket wall. The effects of throat depth and shape of fillet welds on fatigue strength were not significant. Contrary to the expectation, the fatigue strength of the socket welded joint without slip-on gap is higher than that of the joint with the normal gap. A lack of penetration at the root deleteriously reduced fatigue strength, showing 14 MPa in stress amplitude at the 10 7 cycles failure life for the 50 mm diameter socket joint. (orig.)

  14. The Effect of Weld Reinforcement and Post-Welding Cooling Cycles on Fatigue Strength of Butt-Welded Joints under Cyclic Tensile Loading.

    Science.gov (United States)

    Araque, Oscar; Arzola, Nelson; Hernández, Edgar

    2018-04-12

    This research deals with the fatigue behavior of butt-welded joints, by considering the geometry and post-welding cooling cycles, as a result of cooling in quiet air and immersed in water. ASTM A-36 HR structural steel was used as the base metal for the shielded metal arc welding (SMAW) process with welding electrode E6013. The welding reinforcement was 1 mm and 3 mm, respectively; axial fatigue tests were carried out to determine the life and behavior in cracks propagation of the tested welded joints, mechanical characterization tests of properties in welded joints such as microhardness, Charpy impact test and metallographic analysis were carried out. The latter were used as input for the analysis by finite elements which influence the initiation and propagation of cracks and the evaluation of stress intensity factors (SIF). The latter led to obtaining the crack propagation rate and the geometric factor. The tested specimens were analyzed, by taking photographs of the cracks at its beginning in order to make a count of the marks at the origin of the crack. From the results obtained and the marks count, the fatigue crack growth rate and the influence of the cooling media on the life of the welded joint are validated, according to the experimental results. It can be concluded that the welded joints with a higher weld reinforcement have a shorter fatigue life. This is due to the stress concentration that occurs in the vicinity of the weld toe.

  15. Weld repair of helium degraded reactor vessel material

    International Nuclear Information System (INIS)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A.; Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G.

    1990-01-01

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces

  16. Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

  17. Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

    International Nuclear Information System (INIS)

    Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho

    2014-01-01

    We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

  18. Applicability evaluation of eddy current testing for underwater laser beam welding

    International Nuclear Information System (INIS)

    Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

    2010-01-01

    We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

  19. Evaluation of Electron Beam Welding Performance of AA6061-T6 Plate-type Fuel Assembly

    International Nuclear Information System (INIS)

    Kim, Soo-Sung; Seo, Kyoung-Seok; Lee, Don-Bae; Park, Jong-Man; Lee, Yoon-Sang; Lee, Chong-Tak

    2014-01-01

    As one of the most commonly used heat-treatable aluminum alloys, AA6061-T6 aluminum alloy is available in a wide range of structural materials. Typically, it is used in structural members, auto-body sheet and many other applications. Generally, this alloy is easily welded by conventional GTAW (Gas Tungsten Arc Welding), LBW (Laser Beam Welding) and EBW(Electron Beam Welding). However, certain characteristics, such as solidification cracking, porosity, HAZ (Heat-affected Zone) degradation must be considered during welding. Because of high energy density and low heat input, especially LBW and EBW processes possess the advantage of minimizing the fusing zone and HAZ and producing deeper penetration than arc welding processes. In present study, to apply for the plate-type nuclear fuel fabrication and assembly, a fundamental electron beam welding experiment using AA6061-T6 aluminum alloy specimens was conducted. Furthermore, to establish the suitable welding process, and satisfy the requirements of the weld quality, EBW apparatus using an electron welding gun and vacuum chamber was developed, and preliminary investigations for optimizing the welding parameters of the specimens using AA6061-T6 aluminum plates were also performed. The EB weld quality of AA6061-T6 aluminum alloy for the plate-type fuel assembly has been also studied by the weld penetrations of side plate to end fitting and fixing bar and weld inspections using computed tomography

  20. Fracture behavior of unirradiated HT-9 and modified 9Cr-1Mo welds

    International Nuclear Information System (INIS)

    Huang, F.H.; Gelles, D.S.

    1983-05-01

    Fracture toughness tests on HT-9 weld and HAZ samples and modified 9Cr-1Mo weld samples were performed at 93, 205, 427 and 538 0 C. Specimens were of circular compact tension type fabricated from welded material with the notch orientation parallel to the fusion line. The test results were analyzed using the J-integral approach. The results demonstrated that the toughness of HT-9 and 9Cr-1Mo was not significantly reduced due to welding. However, the tearing modulus of the welded material was lower than that of base metal, indicating that the alloys become less resistant to crack propagation as a result of welding

  1. Effect of welding on creep damage evolution in P91B steel

    Energy Technology Data Exchange (ETDEWEB)

    Baral, J., E-mail: jayshree2k4@gmail.com [Metallurgical and Materials Engineering, Indian Institute of Kharagpur, WB 721302 (India); Swaminathan, J. [CSIR–National Metallurgical Laboratory, Jamshedpur 831007 (India); Chakrabarti, D.; Ghosh, R.N. [Metallurgical and Materials Engineering, Indian Institute of Kharagpur, WB 721302 (India)

    2017-07-15

    Study of creep behavior of base metal (without weld) and welded specimens of P91B steel over a range of temperatures (600–650 °C) and stresses (50–180 MPa) showed similar values of minimum creep-rates for both specimens at higher stress regime (>100 MPa) whilst, significantly higher creep rates in the case of welded specimens at lower stress regime. Considering that welded specimen is comprised of two distinct structural regimes, i.e. weld affected zone and base metal, a method has been proposed for estimating the material parameters describing creep behavior of those regimes. Stress–strain distribution across welded specimen predicted from finite element analysis based on material parameters revealed preferential accumulation of stress and creep strain at the interface between weld zone and base metal. This is in-line with the experimental finding that creep rupture preferentially occurs at inter-critical heat affected zone in welded specimens owing to ferrite-martensite structure with coarse Cr{sub 23}C{sub 6} particles. - Highlights: •Comparison of creep properties of welded and virgin specimens of P91B steel. •At lower stresses (<100 MPa) welded samples show higher minimum creep-rate. •Creep rupture at inter-critical heat affected zone (IC-HAZ) in welded specimens. •FEA showing accumulation of creep strain in weld/base metal interface. •Precipitate free soft ferrite matrix accumulates strain and weakens IC-HAZ.

  2. WELDABILITY, WELDING METALLURGY, WELDING CHEMISTRY

    OpenAIRE

    Sarjito Jokosisworo

    2012-01-01

    Sambungan las merupakan bagian penting dari stuktur/bangunan yang dilas, dan kunci dari logam induk yang baik adalah kemampuan las (weld ability). Kemampuan las yang baik dan kemudahan dalam fabrikasi dari suatu logam merupakan pertimbangan dalam memilih suatu logam untuk konstruksi.

  3. Qualification of final closure for disposal container I - applicability of TIG and EBW for overpack welding

    International Nuclear Information System (INIS)

    Asano, H.; Kawahara, K.; Ishii, J.; Shige, T.

    2002-01-01

    Regarding the final sealing technique of the overpack using carbon steel, one of the candidate materials for the disposal container in the geological disposal of high-level radioactive waste in Japan, welding tests were conducted using TIG (GTAW), a typical arc welding process, and electron beam welding (EBW), a high-energy beam welding process. The purpose of the tests was to evaluate the applicability, the scope of the applications and the conditions for the application of the existing techniques; while also examining the welding conditions and the weld quality. Regarding TIG, the optimum welding conditions (the conditions pertaining to the welding procedures and the groove geometry) were checked by using a specimen with a plate thickness of 50 mm, and then circumferential welding tests were conducted for cylindrical specimens with a groove depth of 100 mm and 150 mm. Radiographic testing showed that there was no significant weld defect in the weld and that the welding characteristics were satisfactory. The results of the test of the mechanical properties of the joint were also satisfactory. Measurement of the temperature distribution and the residual stress distribution at the time of the welding was conducted for an evaluation of the residual stress caused by the welding, and an appropriate residual stress analysis method was developed, which confirmed the generation of tensile stress along the circumferential direction of the weld. Then it was pointed out that a necessity of further consideration of how to reduce the stress and to examine the influence that residual stress has on corrosion property. The goal in the EBW test was to achieve a one-pass full penetration welding process for 190 mm while conducting a partial penetration welding test for a welding depth of 80 mm. Subsequent radiographic testing confirmed that there was no significant weld defect. (orig.)

  4. Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

    International Nuclear Information System (INIS)

    Hassanifard, Soran; Zehsaz, Mohammad; Esmaeili, Firooz

    2011-01-01

    In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime. However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints

  5. WELDING PROCESS

    Science.gov (United States)

    Zambrow, J.; Hausner, H.

    1957-09-24

    A method of joining metal parts for the preparation of relatively long, thin fuel element cores of uranium or alloys thereof for nuclear reactors is described. The process includes the steps of cleaning the surfaces to be jointed, placing the sunfaces together, and providing between and in contact with them, a layer of a compound in finely divided form that is decomposable to metal by heat. The fuel element members are then heated at the contact zone and maintained under pressure during the heating to decompose the compound to metal and sinter the members and reduced metal together producing a weld. The preferred class of decomposable compounds are the metal hydrides such as uranium hydride, which release hydrogen thus providing a reducing atmosphere in the vicinity of the welding operation.

  6. Application of Taguchi approach to optimize friction stir welding parameters of polyethylene

    Directory of Open Access Journals (Sweden)

    Bejaoui S.

    2010-06-01

    Full Text Available This paper presents experimental and numerical results of butt friction stir welding of high density polyethylene. The FSW designed tool insulates the welded samples and preserves the heat gained from friction thus avoiding the appearance of blisters and splits after welding. The experimental tests, conducted according to combinations of process factors such as rotation speed, welding speed, pin diameter and hold time at beginning welding, were carried out according the Taguchi orthogonal table L27 in randomized way. Temperatures in the joint during the welding operation and flow stresses from the tensile tests of welded samples were measured and variances were analyzed. Identified models were used to simulate, by finite elements, the tensile tests performed on specimens having a weld cordon in their active area. The results show coherence between the numerical predictions and experimental observations in different cases of weld cordon mechanical behaviour.

  7. Residual stresses in zircaloy welds

    International Nuclear Information System (INIS)

    Santisteban, J. R.; Fernandez, L; Vizcaino, P.; Banchik, A.D.; Samper, R; Martinez, R. L; Almer, J; Motta, A.T.; Colas, K.B; Kerr, M.; Daymond, M.R

    2009-01-01

    Welds in Zirconium-based alloys are susceptible to hydrogen embrittlement, as H enters the material due to dissociation of water. The yield strain for hydride cracking has a complex dependence on H concentration, stress state and texture. The large thermal gradients produced by the applied heat; drastically changes the texture of the material in the heat affected zone, enhancing the susceptibility to delayed hydride cracking. Normally hydrides tend to form as platelets that are parallel to the normal direction, but when welding plates, hydride platelets may form on cooling with their planes parallel to the weld and through the thickness of the plates. If, in addition to this there are significant tensile stresses, the susceptibility of the heat affected zone to delayed hydride cracking will be increased. Here we have measured the macroscopic and microscopic residual stressed that appear after PLASMA welding of two 6mm thick Zircaloy-4 plates. The measurements were based on neutron and synchrotron diffraction experiments performed at the Isis Facility, UK, and at Advanced Photon Source, USA, respectively. The experiments allowed assessing the effect of a post-weld heat treatment consisting of a steady increase in temperature from room temperature to 450oC over a period of 4.5 hours; followed by cooling with an equivalent cooling rate. Peak tensile stresses of (175± 10) MPa along the longitudinal direction were found in the as-welded specimen, which were moderately reduced to (150±10) MPa after the heat-treatment. The parent material showed intergranular stresses of (56±4) MPa, which disappeared on entering the heat-affected zone. In-situ experiments during themal cyclong of the material showed that these intergranular stresses result from the anisotropy of the thermal expansion coefficient of the hexagonal crystal lattice. [es

  8. Fracture toughness of a welded super duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pilhagen, Johan, E-mail: pilhagen@kth.se [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden); Sieurin, Henrik [Scania CV AB, Södertälje (Sweden); Sandström, Rolf [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden)

    2014-06-01

    Fracture toughness testing was conducted on standard single-edge notched bend bar specimens of base and weld metal. The material was the SAF 2906 super duplex stainless steel. The aim was to evaluate the susceptibility for brittle failure at sub-zero temperatures for the base and weld metal. The base metal was tested between −103 and −60 °C and was evaluated according to the crack-tip opening displacement method. The fracture event at and below −80 °C can be described as ductile until critical cleavage initiation occurs, which caused unstable failure of the specimen. The welding method used was submerged arc welding with a 7 wt% nickel filler metal. The welded specimens were post-weld heat treated (PWHT) at 1100 °C for 20 min and then quenched. Energy-dispersive X-ray spectroscopy analysis showed that during PWHT substitutional element partitioning occurred which resulted in decreased nickel content in the ferrite. The PWHT weld metal specimens were tested at −72 °C. The fracture sequence was critical cleavage fracture initiation after minor crack-tip blunting and ductile fracture.

  9. The influence of the weld toe grinding and wig remelting weld toe rehabilitation techniques, on variable stresses, in case of cross fillet welds, reinforced with additional welding rows

    Directory of Open Access Journals (Sweden)

    Babis Claudiu

    2017-01-01

    Full Text Available Variable stresses where the load value varies between a maximum and a minimum value, or varies the position in time, cause after accumulating a large number of load cycles in those structures, the emergence of drug fatigue. Fatigue is characterized by failure on values of the applied stress from the load cycles, below the material flow, values which in case of static stress would not have caused problems. Knowing that the variable stressed structures are sensitive to stress concentrators, the paper aims to highlight the influence of two techniques to reduce stress concentrator weld toe grinding and WIG remelting weld toe, on the behavior of variable tensile test of cross corner welded specimens, reinforced with additional welding rows.

  10. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  11. Tensile properties of four types of austenitic stainless steel welded joints

    International Nuclear Information System (INIS)

    Balladon, P.

    1990-01-01

    In the field of an LMFBR research programme on austenitic stainless steel welds in a Shared Cost Action Safety, Research Area 8, coordinated by JRC-Ispra, four cooperating laboratories (ECN, IKE/MPA, the Welding Institute and UNIREC) have been involved in the fabrication and extensive characterization of welded joints made from one plate of ICL 167 stainless steel. The materials included parent metal, four vacuum electron beam welds, one non vacuum electron beam weld, one submerged arc weld, one gas metal arc weld and one manual metal arc weld. This report summarizes the 106 tensile tests performed at room temperature and 550 0 C, including the influence of strain rate, specimen orientation and welding procedure. Main results are that electron beam welds have tensile properties close to those of parent metal with higher values of yield strength in longitudinal orientation and lower values of total elongation in transverse orientation but with a similar reduction of area, that filler metal welds own the highest values of yield strength and lowest values of ductility. Most of the welds properties are higher than the minimum specified for parent metal, except for some values of total elongation, mainly in transverse orientation. In view of using electron beam welding for production of components used in LMFBR, results obtained show that tensile properties of electron beam welds compare well to those of classical welds. (author)

  12. Fabrication of AA6061-T6 Plate Type Fuel Assembly Using Electron Beam Welding Process

    International Nuclear Information System (INIS)

    Kim, Soosung; Seo, Kyoungseok; Lee, Donbae; Park, Jongman; Lee, Yoonsang; Lee, Chongtak

    2014-01-01

    AA6061-T6 aluminum alloy is easily welded by conventional GTAW (Gas Tungsten Arc Welding), LBW (Laser Beam Welding) and EBW. However, certain characteristics, such as solidification cracking, porosity, HAZ (Heat-affected Zone) degradation must be considered during welding. Because of high energy density and low heat input, especially LBW and EBW processes possess the advantage of minimizing the fusing zone and HAZ and producing deeper penetration than arc welding processes. In present study, to apply for the nuclear fuel plate fabrication and assembly, a fundamental EBW experiment using AA6061-T6 aluminum alloy specimens was conducted. Furthermore, to establish the welding process, and satisfy the requirements of the weld quality, EBW apparatus using an electron welding gun and vacuum chamber was developed, and preliminary investigations for optimizing the welding parameters of the specimens using AA6061-T6 aluminum plates were also performed. The EB weld quality of AA6061-T6 aluminum alloy for the fuel plate assembly has been also studied by the shrinkage measurement and weld inspection using computed tomography. This study was carried out to determine the suitable welding parameters and to evaluate tensile strength of AA6061-T6 aluminum alloy. In the present experiment, satisfactory electron beam welding process of the full-sized sample was being developed. Based on this fundamental study, fabrication of the plate-type fuel assembly will be provided for the future Ki-Jang research reactor project

  13. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  14. El efecto de la heterogeneidad de las propiedades mecánicas de una unión soldada sobre la carga de plastificación de probetas de fractura tipo C(T Y SE(B

    Directory of Open Access Journals (Sweden)

    Donoso, J. R.

    2008-10-01

    Full Text Available The yield load values of two-dimensional C(T and SE(B specimens with various degrees of mismatch, were numerically evaluated. The yield load values were normalized using the Common Format in order to analyze the effect of the weld, using as reference material C(T and SE(B specimens made only of base metal (BM. In undermatched specimens (the weld metal elastic limit is lower than that of BM the normalized yield load decreases compared to the elastic limit of BM. In overmatched specimens (the weld metal elastic limit is larger than that of BM, the yield load increases. This variation of the yield load depends on the degree of mismatch, and on the relation between weld size and crack length. The numerical results were compared with experimental values obtained with mismatched weld C(T specimens using an ASTM A 588 steel as base metal.

    Se determinaron, numéricamente, los valores de la carga de plastificación de probetas de geometría compacta C(T y de flexión SE(B, bidimensionales, con cordón de soldadura de diferentes grados de desajuste entre los límites elásticos del material de soldadura y del metal base. Los valores de la carga de plastificación de las probetas bimetálicas se normalizaron mediante el Formato Común, con el objeto de analizar el efecto del cordón, tomando como referencia probetas de metal base (MB. En probetas sub-ajustadas (límite elástico del cordón menor que el de MB la carga de plastificación normalizada disminuye, comparada con el límite elástico de MB. En probetas sobre-ajustadas (límite elástico del cordón mayor que el de MB se produce un aumento de la carga de plastificación normalizada. Esta variación depende del grado de desajuste, y de la relación entre tamaño de cordón y longitud de grieta. Los resultados numéricos se compararon con valores experimentales obtenidos con probetas C(T de uniones soldadas desajustadas del acero ASTM A 588.

  15. Investigation on fracture toughness of laser beam welded steels

    International Nuclear Information System (INIS)

    Riekehr, S.; Cam, G.; Santos, J.F. dos; Kocak, M.; Klein, R.M.; Fischer, R.

    1999-01-01

    Laser beam welding is currently used in the welding of a variety of structural materials including hot and cold rolled steels, high strength low alloy and stainless steels, aluminium and titanium alloys, refractory and high temperature alloys and dissimilar materials. This high power density welding process has unique advantages of cost effectiveness, low distortion, high welding speed, easy automation, deep penetration, narrow bead width, and narrow HAZ compared to the conventional fusion welding processes. However, there is a need to understand the deformation and fracture properties of laser beam weld joints in order to use this cost effective process for fabrication of structural components fully. In the present study, an austenitic stainless steel, X5CrNi18 10 (1.4301) and a ferritic structural steel, RSt37-2 (1.0038), with a thickness of 4 mm were welded by 5 kW CO 2 laser process. Microhardness measurements were conducted to determine the hardness profiles of the joints. Flat micro-tensile specimens were extracted from the base metal, fusion zone, and heat affected zone of ferritic joint to determine the mechanical property variation across the joint and the strength mismatch ratio between the base metal and the fusion zone. Moreover, fracture mechanics specimens were extracted from the joints and tested at room temperature to determine fracture toughness, Crack Tip Opening Displacement (CTOD), of the laser beam welded specimens. The effect of the weld region strength mis-matching on the fracture toughness of the joints have been evaluated. Crack initiation, crack growth and crack deviation processes have also been examined. These results were used to explain the influence of mechanical heterogeneity of the weld region on fracture behaviour. This work is a part of the ongoing Brite-Euram project Assessment of Quality of Power Beam Weld Joints (ASPOW). (orig.)

  16. Mechanical properties of dissimilar friction welded steel bars in relation to post weld heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Yu Sik; Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of)

    2006-04-15

    Dissimilar friction welding were produced using 15(mm) diameter solid bar in chrome molybedenum steel(KS SCM440) to carbon steel(KS S45C) to investigate their mechanical properties. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, Vickers hardness surveys of the bond of area and H.A.Z and microstructure investigations. The specimens were tested as-welded and Post-Weld Heat Treated(PWHT). The tensile strength of the friction welded steel bars was increased up to 100% of the S45C base metal under the condition of all heating time. Optimal welding conditions were n=2,000(rpm), P{sub 1}=60(MPa), P{sub 2}=100(MPa), t{sub 1}=4(s), t{sub 2}=5(s) when the total upset length is 5.4 and 5.7(mm), respectively. The peak of hardness distribution of the friction welded joints can be eliminated by PWHT. Two different kinds of materials are strongly mixed to show a well-combined structure of macro-particles without any molten material and particle growth or any defects.

  17. The fracture toughness of Type 316 steel and weld metal

    International Nuclear Information System (INIS)

    Picker, C.

    This paper describes the results of fracture toughness tests on Type 316 steel and Manual Metal Arc (MMA) weld metal over a range of temperatures from 20 deg. C to 550 deg. C, and includes the effects on toughness of specimen size, post weld heat treatment and thermal ageing. The conclusions reached are that Type 316 steel possesses a superior toughness to the weld metal in the as-welded or stress relieved conditions but the toughness of the steel is degraded to a level similar to that of the weld metal following thermal ageing at temperatures over 600 deg. C. Relatively short term thermal ageing in the temperature range 370 deg. C to 450 deg. C does not appear to affect the toughness of either Type 316 steel or weld metal. (author)

  18. Post-irradiation mechanical tests on F82H EB and TIG welds

    International Nuclear Information System (INIS)

    Rensman, J.; Osch, E.V. van; Horsten, M.G.; D'Hulst, D.S.

    2000-01-01

    The irradiation behaviour of electron beam (EB) and tungsten inert gas (TIG) welded joints of the reduced-activation martensitic steel IEA heat F82H-mod. was investigated by neutron irradiation experiments in the high flux reactor (HFR) in Petten. Mechanical test specimens, such as tensile specimens and KLST-type Charpy impact specimens, were neutron irradiated up to a dose level of 2-3 dpa at a temperature of 300 deg. C in the HFR reactor in Petten. The tensile results for TIG and EB welds are as expected with practically no strain hardening capacity left. Considering impact properties, there is a large variation in impact properties for the TIG weld. The irradiation tends to shift the DBTT of particularly the EB welds to very high values, some cases even above +250 deg. C. PWHT of EB-welded material gives a significant improvement of the DBTT and USE compared to the as-welded condition

  19. Investigation of TIG welding characteristics with a dual cooled rod for the fuel irradiation test

    International Nuclear Information System (INIS)

    Kim, Soo Sung; Kim, Hyung Kyu

    2008-01-01

    To establish the fabrication process, and for satisfying the requirements of the irradiation test, an TIG(Tungsten Inert Gas) welding machine for the dual cooled rods specimens was developed, and the preliminary welding experiments were performed to optimize the welding process conditions. Cladding tubes of 15.9 and 9 mm for the outer and inner diameters, respectively with a 0.57 mm thickness and end caps were used for the specimens. This paper describes the experimental results of the TIG welds and the micrograph examinations of the TIG welded specimens corresponding to various welding conditions for the dual cooled fuel irradiation test. The investigations revealed that the present TIG process satisfied the requirements for the fuel irradiation test in the HANARO research reactor

  20. Mechanical properties and corrosion behaviour of MIG welded 5083 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Durmus, Huelya [Celal Bayar Univ., Turgutlu-Manisa (Turkey)

    2011-07-01

    For this study 5083 Aluminium alloy plates, as used in automobiles and watercraft, were experimentally MIG welded. The plates were joined with different wires and at various currents. The effects of welding with different parameters on the mechanical and corrosion properties were investigated. The corrosion behaviour of the MIG welded 5083 Aluminium base material was also investigated. The effects of the chemical composition of the filler material on the mechanical properties were examined by metallographic inspection and tensile testing. By EDS and XRD analyses of specimens it turned out that different structures in the weld metal (Cu3Si) affect its mechanical properties. The mechanical properties of the specimens welded with 5356 filler metal were found as quite well improved as compared to those specimens welded with 4043 and 5183 filler material. The results of the metallographic analysis, and mechanical and corrosion tests exhibited that the 5356 filler material was most suitable for the 5083 Al alloy base material. (orig.)

  1. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

    This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

  2. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ

  3. Welding and cutting

    International Nuclear Information System (INIS)

    Drews, P.; Schulze Frielinghaus, W.

    1978-01-01

    This is a survey, with 198 literature references, of the papers published in the fields of welding and cutting within the last three years. The subjects dealt with are: weldability of the materials - Welding methods - Thermal cutting - Shaping and calculation of welded joints - Environmental protection in welding and cutting. (orig.) [de

  4. Mechanical properties of CO2/MIG welded structural rolled steel and stainless steel

    International Nuclear Information System (INIS)

    Lim, Jong Young; Yoon, Myong Jin; Kim, Sang Youn; Kim, Tae Gyu; Shin, Hyeon Seung

    2015-01-01

    To accomplish long-term use of specific parts of steel, welding technology is widely applied. In this study, to compare the efficiency in improving mechanical properties, rolled steel (SS400) was welded with stainless steel (STS304) by both CO 2 welding method and MIG (metal inert gas) welding method, respectively. Multi-tests were conducted on the welded specimen, such as X-ray irradiation, Vickers' Hardness, tensile test, fatigue test and fatigue crack growth test. Based on the fatigue crack growth test performed by two different methods, the relationship of da/dN was analyzed. Although the hardness by the two methods was similar, tensile test and fatigue properties of MIG welded specimen are superior to CO 2 welded one.

  5. Development of Alternative Technology to PWHT in Site Welding

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Lee, B. S.; Jang, J. S.; Kim, K. H.; Park, S. D.; Yoon, J. H.; Kim, M. C.; Kim, K. B.; Sung, K. W

    2007-04-15

    ASME Section IX added requirements for qualification when using temper bead welding in the 2004 edition. The temper bead welding techniques which can satisfy the requirements of the Code are needed to use them in the site repair welding. The optimized welding parameters can be obtained when controlling the process to supercritically-reheat and to subcritically-reheat the coarse grain region sequently. The microstructures of SCFGCG obtained from the Gleegle simulated specimens and those of post weld heat treated coarse grain region are compared. The obtained both microstructures showed almost similar patterns. mid bead deposition technique Suggested in this study has a technical concept that the mid beads are deposited between the deposited initial beads repeatedly in a bead layer, which gives a lot of reheating effects on brittle microstructure in HAZ. This newly suggested technique is considered to have more effective tempering effect than the conventional temper bead technique which has concept to deposit one type of beads in a bead layer. The suggested modeling in this study can simulate well the SMAW process. Hence this modeling was used in analyzing the more complicated welding process of multi-layer welding. The modeling was used to analyze the tempering effect on the microstructures of HAZ by considering the patterns of overlapping of the reheating regions under the consequently deposited beads. When considering the crack path in the ever-matched weld metal condition, the interface may have a resistance against the crack propagation. A182 filler and A625 filler were used to make the weld specimens which have different weld metal conditions. The crack directed toward the under-matched weld metal may propagate across the fusion line easier than that of the even-matched weld metal condition.

  6. Development of Alternative Technology to PWHT in Site Welding

    International Nuclear Information System (INIS)

    Lee, Ho Jin; Lee, B. S.; Jang, J. S.; Kim, K. H.; Park, S. D.; Yoon, J. H.; Kim, M. C.; Kim, K. B.; Sung, K. W.

    2007-04-01

    ASME Section IX added requirements for qualification when using temper bead welding in the 2004 edition. The temper bead welding techniques which can satisfy the requirements of the Code are needed to use them in the site repair welding. The optimized welding parameters can be obtained when controlling the process to supercritically-reheat and to subcritically-reheat the coarse grain region sequently. The microstructures of SCFGCG obtained from the Gleegle simulated specimens and those of post weld heat treated coarse grain region are compared. The obtained both microstructures showed almost similar patterns. mid bead deposition technique Suggested in this study has a technical concept that the mid beads are deposited between the deposited initial beads repeatedly in a bead layer, which gives a lot of reheating effects on brittle microstructure in HAZ. This newly suggested technique is considered to have more effective tempering effect than the conventional temper bead technique which has concept to deposit one type of beads in a bead layer. The suggested modeling in this study can simulate well the SMAW process. Hence this modeling was used in analyzing the more complicated welding process of multi-layer welding. The modeling was used to analyze the tempering effect on the microstructures of HAZ by considering the patterns of overlapping of the reheating regions under the consequently deposited beads. When considering the crack path in the ever-matched weld metal condition, the interface may have a resistance against the crack propagation. A182 filler and A625 filler were used to make the weld specimens which have different weld metal conditions. The crack directed toward the under-matched weld metal may propagate across the fusion line easier than that of the even-matched weld metal condition

  7. Microhardness Testing of Aluminum Alloy Welds

    Science.gov (United States)

    Bohanon, Catherine

    2009-01-01

    A weld is made when two pieces of metal are united or fused together using heat or pressure, and sometimes both. There are several different types of welds, each having their own unique properties and microstructure. Strength is a property normally used in deciding which kind of weld is suitable for a certain metal or joint. Depending on the weld process used and the heat required for that process, the weld and the heat-affected zone undergo microstructural changes resulting in stronger or weaker areas. The heat-affected zone (HAZ) is the region that has experienced enough heat to cause solid-state microstructural changes, but not enough to melt the material. This area is located between the parent material and the weld, with the grain structure growing as it progresses respectively. The optimal weld would have a short HAZ and a small fluctuation in strength from parent metal to weld. To determine the strength of the weld and decide whether it is suitable for the specific joint certain properties are looked at, among these are ultimate tensile strength, 0.2% offset yield strength and hardness. Ultimate tensile strength gives the maximum load the metal can stand while the offset yield strength gives the amount of stress the metal can take before it is 0.2% longer than it was originally. Both of these are good tests, but they both require breaking or deforming the sample in some way. Hardness testing, however, provides an objective evaluation of weld strengths, and also the difference or variation in strength across the weld and HAZ which is difficult to do with tensile testing. Hardness is the resistance to permanent or plastic deformation and can be taken at any desired point on the specimen. With hardness testing, it is possible to test from parent metal to weld and see the difference in strength as you progress from parent material to weld. Hardness around grain boundaries and flaws in the material will show how these affect the strength of the metal while still

  8. Advanced Welding Applications

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

  9. A comparative study of pulsed Nd:YAG laser welding and TIG welding of thin Ti6Al4V titanium alloy plate

    International Nuclear Information System (INIS)

    Gao, Xiao-Long; Zhang, Lin-Jie; Liu, Jing; Zhang, Jian-Xun

    2013-01-01

    This paper reports on a study aiming at comparing properties of the Ti6Al4V titanium alloy joints between pulsed Nd:YAG laser welding and traditional fusion welding. To achieve the research purpose, Ti6Al4V titanium alloy plates with a thickness of 0.8 mm were welded using pulsed Nd:YAG laser beam welding (LBW) and gas tungsten arc welding (TIG), respectively. Residual distortions, weld geometry, microstructure and mechanical properties of the joints produced with LBW and TIG welding were compared. During the tensile test, with the aid of a high speed infrared camera, evolution of the plastic strain within tensile specimens corresponding to LBW and TIG welding were recorded and analyzed. Compared with the TIG, the welded joint by LBW has the characters of small overall residual distortion, fine microstructure, narrow heat-affected zone (HAZ), high Vickers hardness. LBW welding method can produce joints with higher strength and ductility. It can be concluded that Pulsed Nd:YAG laser welding is much more suitable for welding the thin Ti6Al4V titanium alloy plate than TIG welding.

  10. Laparoscopic specimen retrieval bags.

    Science.gov (United States)

    Smorgick, Noam

    2014-10-01

    Specimen retrieval bags have long been used in laparoscopic gynecologic surgery for contained removal of adnexal cysts and masses. More recently, the concerns regarding spread of malignant cells during mechanical morcellation of myoma have led to an additional use of specimen retrieval bags for contained "in-bag" morcellation. This review will discuss the indications for use retrieval bags in gynecologic endoscopy, and describe the different specimen bags available to date.

  11. Weld Growth Mechanisms and Failure Behavior of Three-Sheet Resistance Spot Welds Made of 5052 Aluminum Alloy

    Science.gov (United States)

    Li, Yang; Yan, Fuyu; Luo, Zhen; Chao, Y. J.; Ao, Sansan; Cui, Xuetuan

    2015-06-01

    This paper investigates the weld nugget formation in three-sheet aluminum alloy resistance spot welding. The nugget formation process in three equal thickness sheets and three unequal thickness sheets of 5052 aluminum alloy were studied. The results showed that the nugget was initially formed at the workpiece/workpiece interfaces (i.e., both upper interface and lower interface). The two small nuggets then grew along the radial direction and axial direction (welding direction) as the welding time increased. Eventually, the two nuggets fused into one large nugget. During the welding process, the Peltier effect between the Cu-Al caused the shift of the nugget in the welding direction. In addition, the mechanical strength and fracture mode of the weld nuggets at the upper and lower interfaces were also studied using tensile shear specimen configuration. Three failure modes were identified, namely interfacial, mixed, and pullout. The critical welding time and critical nugget diameter corresponding to the transitions of these modes were investigated. Finally, an empirical failure load formula for three-sheet weld similar to two-sheet spot weld was developed.

  12. MICROSTRUCTURE AND FATIGUE PROPERTIES OF DISSIMILAR SPOT WELDED JOINTS OF AISI 304 AND AISI 1008

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2013-06-01

    Full Text Available Carbon steel and stainless steel composites are being more frequently used for applications requiring a corrosion resistant and attractive exterior surface and a high strength structural substrate. Spot welding is a potentially useful and efficient jointing process for the production of components consisting of these two materials. The spot welding characteristics of weld joints between these two materials are discussed in this paper. The experiment was conducted on dissimilar weld joints using carbon steel and 304L (2B austenitic stainless steel by varying the welding currents and electrode pressing forces. Throughout the welding process; the electrical signals from the strain sensor, current transducer and terminal voltage clippers are measured in order to understand each and every millisecond of the welding process. In doing so, the dynamic resistances, heat distributions and forging forces are computed for various currents and force levels within the good welds’ regions. The other process controlling parameters, particularly the electrode tip and weld time, remained constant throughout the experiment. The weld growth was noted for the welding current increment, but in the electrode force increment it causes an adverse reaction to weld growth. Moreover, the effect of heat imbalance was clearly noted during the welding process due to the different electrical and chemical properties. The welded specimens finally underwent tensile, hardness and metallurgical testing to characterise the weld growth.

  13. Fiber Laser Welding of Dissimilar 2205/304 Stainless Steel Plates

    Directory of Open Access Journals (Sweden)

    Ghusoon Ridha Mohammed

    2017-12-01

    Full Text Available In this study, an attempt on pulsed-fiber laser welding on an austenitic-duplex stainless steel butt joint configuration was investigated. The influence of various welding parameters, such as beam diameter, peak power, pulse repetition rate, and pulse width on the weld beads geometry was studied by checking the width and depth of the welds after each round of welding parameters combination. The weld bead dimensions and microstructural progression of the weld joints were observed microscopically. Finally, the full penetration specimens were subjected to tensile tests, which were coupled with the analysis of the fracture surfaces. From the results, combination of the selected weld parameters resulted in robust weldments with similar features to those of duplex and austenitic weld metals. The weld depth and width were found to increase proportionally to the laser power. Furthermore, the weld bead geometry was found to be positively affected by the pulse width. Microstructural studies revealed the presence of dendritic and fine grain structures within the weld zone at low peak power, while ferritic microstructures were found on the sides of the weld metal near the SS 304 and austenitic-ferritic microstructure beside the duplex 2205 boundary. Regarding the micro-hardness tests, there was an improvement when compared to the hardness of duplex and austenitic stainless steels base metals. Additionally, the tensile strength of the fiber laser welded joints was found to be higher when compared to the tensile strength of the base metals (duplex and austenitic in all of the joints.

  14. Creep-fatigue propagation of semi-elliptical crack at 650 deg. C in 316L(N) stainless steel plates with or without welded joints

    International Nuclear Information System (INIS)

    Curtit, F.

    2000-01-01

    This study realised in LISN Laboratory of CEA Saclay, deals with the creep fatigue propagation of semi elliptical crack at the temperature of 650 deg C in 316L(N) stainless steel plates with or without welded joints. A vast majority of the studies on creep fatigue propagation models are based on specimen (CT) especially designed for crack propagation study. The PLAQFLU program performed in LISN laboratory deals with the application and adaptation of these models to complex crack shape, which are more representative of the cracks observed in industrial components. In this scope, we use propagation tests realised at the temperature of 650 deg C with wide plates containing semi elliptical defects. For some of them, the initial defect is machined in the middle of a welded joint, which constitute a privileged site for the crack initiation. The approach used in this study is based on global parameters of fracture mechanics. At first, tests on CT specimen are used in order to determine the propagation laws correlating the crack growth rate to the global parameters K or C * . These laws are then supposed to be intrinsic to our materials and are used to analysed the semi elliptical crack propagation. The analysis of the comportment of the crack during the hold time demonstrates the possibility to establish a correlation between the crack propagation both in the deepest and the surface point and the local value of C * . These correlations are coherent in the different points of the crack front for the different applied hold times, and they present a reasonably good agreement with the creep propagation law identified on CT specimen. The simulation of test performed on based metal specimen with a model of summation of both creep and pure fatigue crack growth gives acceptable results when the calculus of the simplified expression of C * s considers a continuous evolution of creep deformations rate during the all test. (author)

  15. Prediction of deformations during gas-tungsten-arc stationary welds

    International Nuclear Information System (INIS)

    Duncan, D.B.; Giedt, W.H.

    1980-10-01

    Local temperature measurements on the heated and unheated surfaces, and strain measurements on the unheated surfaces of unrestrained circular weld specimens of annealed and cold-rolled Nitronic 40 stainless steel during stationary welding, are compared with values predicted from finite-element programs for temperature and strain variations. Experimental and predicted temperature histories agree within 10%. Predicted and measured hoop strain profiles (using a moire fringe technique), for the unheated surface are compared, showing significant deviations near the central region. Transient deflection measurements of the unheated specimen surfaces show good agreement with theory during the period the arc is operating. Close agreement in deflection behavior was observed during the cooling portion of the weld cycle for the annealed specimen, whereas substantial deviations occurred for the cold-rolled specimens

  16. Predicting failure response of spot welded joints using recent extensions to the Gurson model

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2010-01-01

    The plug failure modes of resistance spot welded shear-lab and cross-tension test specimens are studied, using recent extensions to the Gurson model. A comparison of the predicted mechanical response is presented when using either: (i) the Gurson-Tvergaard-Needleman model (GTN-model), (ii...... is presented. The models are applied to predict failure of specimens containing a fully intact weld nugget as well as a partly removed weld nugget to address the problems of shrinkage voids or larger weld defects. All analysis are carried out by full 3D finite element modelling....

  17. Plastic fracture toughness of austenitic welding connection for Ver-1000 nuclear reactor piping of 300-350 mm diameter

    International Nuclear Information System (INIS)

    Vasil'chenko, G.S.; Dragunov, Yu.G.; Kabelevskij, M.G.; Kazantsev, A.G.; Kunavin, S.A.; Merinov, G.N.; Sokov, L.M.

    2000-01-01

    The outside welding technology for circular welds in a pearlitic tube using austenitic welding wire materials is developed and applied in manufacturing pipelines of CPP and ECC. Mechanical properties and fracture toughness of austenitic welded joints in pearlitic tubes are determined to substantiate by calculation the practicality of the leakage prior to failure concept. The work is accomplished on experimental tube manufactured by hand arc welding. When manufactured the tube is cut into 5 rings. From the rings the tensile specimens are cut for testing at 20 and 350 deg C as well as Charpy V-notch impact specimens and compact specimens ST-1T. It is shown that the materials of the experimental tube meet the standard requirements. Only axial specimens cut across the weld are not in conformity with the requirements for specific elongation [ru

  18. Strength evaluation of jointed parts between ODS cladding and end plug by means of alternative welding method. Research report

    International Nuclear Information System (INIS)

    Hatakeyama, Koichi; Mizuta, Syunji; Fujiwara, Masayuki; Ukai, Shigeharu

    2001-12-01

    For the purpose of urgently discerning the applicability of ODS cladding tube to the long life core of the fast reactors, the irradiation test using Russian fast reactor BOR-60 is planned. In this irradiation test, TIG welding or laser welding will be applied as welding method of ODS cladding with end plug. In this report, applicability of alternative welding method, i.e., TIG welding, laser welding, and also electron beam welding and 3 kinds of brazing diffusion bonding technique was evaluated. In addition, bending test and internal creep rupture test of the samples which were welded by laser and TIG welding were carried out. Following results were obtained in this study. (1) Tensile strength of laser welding test specimens with the highest energy density is most excellent in the welding process (over 90% of the base metal strength). (2) In the brazing filler metal, the tensile strength of the nickel brazing was most excellent (over 84% of the base metal strength). (3) In the bending test of laser and TIG welded test specimens, the crack was generated in circumferential direction of weld zone, which relatively corresponds to small bending angle. (4) As result of internal creep rupture test at 700degC, cladding itself was ruptured in the high stress region, whereas, weld zone was ruptured in the low stress level. (author)

  19. Effects Of Welding On The Fatigue Behaviour Of Commercial Aluminum AA-1100 Joints

    Science.gov (United States)

    Uthayakumar, M.; Balasubramanian, V.; Rani, Ahmad Majdi Abdul; Hadzima, Branislav

    2018-04-01

    Friction Stir Welding (FSW) is an budding solid state welding process, which is frequently used for joining aluminum alloys where materials can be joined without melt and recast. Therefore, when welding alloys through FSW the phase transformations occurs will be in the solid state form. The present work is aimed in evaluating the fatigue life of friction stir welded commercial grade aluminum alloy joints. The commercial grade AA1100 aluminum alloy of 12mm thickness plate is welded and the specimens are tested using a rotary beam fatigue testing machine at different stress levels. The stress versus number of cycles (S-N) curves was plotted using the data points. The Fatigue life of tungsten inert gas (TIG) and metal inert gas (MIG) welded joints was compared. The fatigue life of the weld joints was interrelated with the tensile properties, microstructure and micro hardness properties. The effects of the notches and welding processes are evaluated and reported.

  20. Comparative study of TIG and SMAW root welding passes on ductile iron cast weldability

    Directory of Open Access Journals (Sweden)

    J. Cárcel-Carrasco

    2017-01-01

    Full Text Available This work compares the weldability of ductile iron when: (I a root weld is applied with a tungsten inert gas (TIG process using an Inconel 625 source rod and filler welds are subsequently applied using coated electrodes with 97,6%Ni; and (II welds on ductile iron exclusively made using the manual shielded metal arc welding technique (SMAW. Both types of welds are performed on ductile iron specimen test plates that are subjected to preheat and post-weld annealing treatments. Samples with TIG root-welding pass shown higher hardness but slightly lower ductility and strength. Both types of welding achieved better ductile and strength properties than ones found in literature.

  1. Selected Welding Techniques, Part 2

    National Research Council Canada - National Science Library

    1964-01-01

    Partial contents: CONVENTIONAL WELD JOINTS VERSUS BUTT JOINTS IN 1-INCH ALUMINUM PLATE, SPECIAL WELD JOINT PREPARATION, UPSET METAL EDGES FOR INCREASED WELD JOINT STRENGTH, OUT-OF-POSITION WELDING OF HEAVY GAGE...

  2. Microstructure and mechanical properties of friction stir welded and laser welded high entropy alloy CrMnFeCoNi

    Science.gov (United States)

    Jo, Min-Gu; Kim, Han-Jin; Kang, Minjung; Madakashira, Phaniraj P.; Park, Eun Soo; Suh, Jin-Yoo; Kim, Dong-Ik; Hong, Sung-Tae; Han, Heung Nam

    2018-01-01

    The high entropy alloy CrMnFeCoNi has been shown to have promising structural properties. For a new alloy to be used in a structural application it should be weldable. In the present study, friction stir welding (FSW) and laser welding (LW) techniques were used to butt weld thin plates of CrMnFeCoNi. The microstructure, chemical homogeneity and mechanical behavior of the welds were characterized and compared with the base metal. The tensile stress-strain behavior of the welded specimens were reasonable when compared with that of the base metal. FSW refined the grain size in the weld region by a factor of ˜14 when compared with the base metal. High-angle annular dark field transmission electron microscopy in combination with energy dispersive X-ray spectroscopy showed chemical inhomogeneity between dendritic and interdendritic regions in the fusion zone of LW. Large fluctuations in composition (up to 15 at%) did not change the crystal structure in the fusion zone. Hardness measurements were carried out in the weld cross section and discussed in view of the grain size, low angle grain boundaries and twin boundaries in FSW specimens and the dendritic microstructure in LW specimens.

  3. The detection of tightly closed flaws by nondestructive testing (NDT) methods. [fatigue crack formation in aluminum alloy test specimens

    Science.gov (United States)

    Rummel, W. D.; Rathke, R. A.; Todd, P. H., Jr.; Mullen, S. J.

    1975-01-01

    Liquid penetrant, ultrasonic, eddy current and X-radiographic techniques were optimized and applied to the evaluation of 2219-T87 aluminum alloy test specimens in integrally stiffened panel, and weld panel configurations. Fatigue cracks in integrally stiffened panels, lack-of-fusion in weld panels, and fatigue cracks in weld panels were the flaw types used for evaluation. A 2319 aluminum alloy weld filler rod was used for all welding to produce the test specimens. Forty seven integrally stiffened panels containing a total of 146 fatigue cracks, ninety three lack-of-penetration (LOP) specimens containing a total of 239 LOP flaws, and one-hundred seventeen welded specimens containing a total of 293 fatigue cracks were evaluated. Nondestructive test detection reliability enhancement was evaluated during separate inspection sequences in the specimens in the 'as-machined or as-welded', post etched and post proof loaded conditions. Results of the nondestructive test evaluations were compared to the actual flaw size obtained by measurement of the fracture specimens after completing all inspection sequences. Inspection data were then analyzed to provide a statistical basis for determining the flaw detection reliability.

  4. Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

    Science.gov (United States)

    Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

    2017-05-01

    findings, the hardness results for ESW were lower than those usually observed for other electric arc welding processes. In addition, specimens subject to bending tests performed in accordance with the current standards used for qualification of welding procedures were approved. These evidences allow the conclusion that the ESW process can provide deposits with high quality despite the high welding energy levels, in order to achieve the desired productivity, being an interesting alternative for AISI 904L weld overlays.

  5. Georeferencing Animal Specimen Datasets

    NARCIS (Netherlands)

    van Erp, M.G.J.; Hensel, R.; Ceolin, D.; van der Meij, M.

    2014-01-01

    For biodiversity research, the field of study that is concerned with the richness of species of our planet, it is of the utmost importance that the location of an animal specimen find is known with high precision. Due to specimens often having been collected over the course of many years, their

  6. Residual stress improvement in multi-layer welded plates using water-shower cooling during welding process

    International Nuclear Information System (INIS)

    Yanagida, Nobuyoshi; Koide, Hiroo

    2006-01-01

    To reduce tensile residual stress in a welded region, we developed a new welding method that applies a water-shower behind the welding torch. When this method is applied to welding of austenitic stainless steel plates, cooling conditions mainly determine how much the residual stress can be reduced. To determine the conditions, we first used FEM to evaluate the effects of interpass temperature on the residual stress. And we found effective conditions for reducing tensile residual stress. To verify the validity of the conditions, specimens welded with or without water shower cooling were manufactured. Residual stresses of the specimens were experimentally measured. It was found that tensile residual stresses were generated on the surface of the welds and those were reduced in the case that the water-shower was applied. These measurement results agree well with the FEM analyses. It can therefore be concluded that the water-shower cooling during welding is appropriate for reducing tensile residual stress in austenitic stainless steel welding. (author)

  7. Weld-brazing - a new joining process. [combination resistance spot welding and brazing of titanium alloys

    Science.gov (United States)

    Bales, T. T.; Royster, D. M.; Arnold, W. E., Jr.

    1972-01-01

    A joining process designated weld brazing which combines resistance spot welding and brazing has been developed. Resistance spot welding is used to position and align the parts as well as to establish a suitable faying surface gap for brazing. Fabrication is then completed by capillary flow of the braze alloy into the joint. The process has been used successfully to fabricate Ti-6Al-4V titanium alloy joints using 3003 aluminum braze alloy. Test results obtained on single overlap and hat-stiffened structural specimens show that weld brazed joints are superior in tensile shear, stress rupture, fatigue, and buckling than joint fabricated by spotwelding or brazing. Another attractive feature of the process is that the brazed joints is hermetically sealed by the braze material.

  8. Numerical aspects for efficient welding computational mechanics

    Directory of Open Access Journals (Sweden)

    Aburuga Tarek Kh.S.

    2014-01-01

    Full Text Available The effect of the residual stresses and strains is one of the most important parameter in the structure integrity assessment. A finite element model is constructed in order to simulate the multi passes mismatched submerged arc welding SAW which used in the welded tensile test specimen. Sequentially coupled thermal mechanical analysis is done by using ABAQUS software for calculating the residual stresses and distortion due to welding. In this work, three main issues were studied in order to reduce the time consuming during welding simulation which is the major problem in the computational welding mechanics (CWM. The first issue is dimensionality of the problem. Both two- and three-dimensional models are constructed for the same analysis type, shell element for two dimension simulation shows good performance comparing with brick element. The conventional method to calculate residual stress is by using implicit scheme that because of the welding and cooling time is relatively high. In this work, the author shows that it could use the explicit scheme with the mass scaling technique, and time consuming during the analysis will be reduced very efficiently. By using this new technique, it will be possible to simulate relatively large three dimensional structures.

  9. Closeout of JOYO-1 Specimen Fabrication Efforts

    International Nuclear Information System (INIS)

    ME Petrichek; JL Bump; RF Luther

    2005-01-01

    Fabrication was well under way for the JOYO biaxial creep and tensile specimens when the NR Space program was canceled. Tubes of FS-85, ASTAR-811C, and T-111 for biaxial creep specimens had been drawn at True Tube (Paso Robles, CA), while tubes of Mo-47.5 Re were being drawn at Rhenium Alloys (Cleveland, OH). The Mo-47.5 Re tubes are now approximately 95% complete. Their fabrication and the quantities produced will be documented at a later date. End cap material for FS-85, ASTAR-811C, and T-111 had been swaged at Pittsburgh Materials Technology, Inc. (PMTI) (Large, PA) and machined at Vangura (Clairton, PA). Cutting of tubes, pickling, annealing, and laser engraving were in process at PMTI. Several biaxial creep specimen sets of FS-85, ASTAR-811C, and T-111 had already been sent to Pacific Northwest National Laboratory (PNNL) for weld development. In addition, tensile specimens of FS-85, ASTAR-811C, T-111, and Mo-47.5 Re had been machined at Kin-Tech (North Huntington, PA). Actual machining of the other specimen types had not been initiated. Flowcharts 1-3 detail the major processing steps each piece of material has experienced. A more detailed description of processing will be provided in a separate document [B-MT(SRME)-51]. Table 1 lists the in-process materials and finished specimens. Also included are current metallurgical condition of these materials and specimens. The available chemical analyses for these alloys at various points in the process are provided in Table 2

  10. Study on the application of thickened welds without post weld heat treatment for containment vessels

    International Nuclear Information System (INIS)

    Takeuchi, T.; Fukaya, T.; Sato, M.; Takano, G.

    1978-01-01

    As material for containment vessels, SGV49 steel plates are mainly used. However, those used for this purpose are limited in thickness to smaller than 38 mm. This is because the present standard requires welds thicker than 38 mm to be subjected to post weld heat treatment but operation on the site is practically difficult. In the case of 3-loop containment vessels of pressurized water type reactors, use of 38 mm SGV49 brings an increase in their height and this is disadvantageous from a seismic viewpoint. Therefore, use of 45 mm-thick steel material has become necessary in order to increase design internal pressure and reduce the height of the vessels. To investigate the propriety of the use of 45 mm-thick SGV49 for this purpose without post weld heat treatment we investigated the basic performances of base metal and welded joints. We also conducted large-scale embrittlement fracture tests (CT test, deep notch test, wide plate tensile test and ESSO test) in order to examine whether welds not subjected to post weld heat treatment are safe against embrittlement fracture under the operating conditions of the vessels. The results proved that the welds of SGV49 steel plates are safe enough under the operating conditions. (author)

  11. Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    Day, S D; Wong, F G; Gordon, S R; Wong, L L; Rebak, R B

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCl at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  12. Electrochemical Testing of Gas Tungsten ARC Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    S. Daniel Day; Frank M.G. Wong; Steven R. Gordon; Lana L. Wong; Raul B. Rebak

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIC method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCI at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  13. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    International Nuclear Information System (INIS)

    Mizuno, R.; Matsuda, F.; Brziak, P.; Lomozik, M.

    2004-01-01

    Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

  14. Phase-contrast x-ray computed tomography for observing biological specimens and organic materials

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji

    1995-02-01

    A novel three-dimensional x-ray imaging method has been developed by combining a phase-contrast x-ray imaging technique with x-ray computed tomography. This phase-contrast x-ray computed tomography (PCX-CT) provides sectional images of organic specimens that would produce absorption-contrast x-ray CT images with little contrast. Comparing PCX-CT images of rat cerebellum and cancerous rabbit liver specimens with corresponding absorption-contrast CT images shows that PCX-CT is much more sensitive to the internal structure of organic specimens.

  15. Low Cycle Fatigue Behavior of Alloy 617 Base Metal and Welded Joints at Room Temperature and 850 .deg. C for VHTR Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Jin; Dew, Rando T. [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Min Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Low cycle fatigue (LCF) is an important design consideration for high temperature IHX components. Moreover, some of the components are joined by welding techniques and therefore the welded joints are unavoidable in the construction of mechanical structures. Since Alloy 617 was introduced in early 1970s, many attempts have been made in the past two decades to evaluate the LCF and creep-fatigue behavior in Alloy 617 base metal at room temperature and high temperature. However, little research has focused on the evaluation and characterization of the Alloy 617 welded joints. butt-welded joint specimens was performed at room temperature and 850 .deg. C. Fatigue lives of GTAW welded joint specimens were lower than those of base metal specimens. LCF cracking and failure in welded specimens initiated in the weld metal zone and followed transgranluar dendritic paths for both at RT and 850 .deg. C.

  16. Automatic welding of fuel elements

    International Nuclear Information System (INIS)

    Briola, J.

    1958-01-01

    The welding process depends on the type of fuel element, the can material and the number of cartridges to be welded: - inert-gas welding (used for G2 and the 1. set of EL3), - inert atmosphere arc welding (used for welding uranium and zirconium), - electronic welding (used for the 2. set of EL3 and the tank of Proserpine). (author) [fr

  17. Detecting flaws in welds

    International Nuclear Information System (INIS)

    Woodacre, A.; Lawton, H.

    1979-01-01

    An apparatus and a method for detecting flaws in welds in a workpiece, the portion of the workpiece containing the weld is maintained at a constant temperature and the weld is scanned by an infra red detector. The weld is then scanned again with the workpiece in contact with a cooling probe to produce a steeper temperature gradient across the weld. Comparison of the signals produced by each scan reveals the existence of defects in the welds. The signals may be displayed on an oscilloscope and the display may be observed by a TV camera and recorded on videotape. (UK)

  18. Fusion welding process

    Science.gov (United States)

    Thomas, Kenneth C.; Jones, Eric D.; McBride, Marvin A.

    1983-01-01

    A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

  19. A benchmark on computational simulation of a CT fracture experiment

    International Nuclear Information System (INIS)

    Franco, C.; Brochard, J.; Ignaccolo, S.; Eripret, C.

    1992-01-01

    For a better understanding of the fracture behavior of cracked welds in piping, FRAMATOME, EDF and CEA have launched an important analytical research program. This program is mainly based on the analysis of the effects of the geometrical parameters (the crack size and the welded joint dimensions) and the yield strength ratio on the fracture behavior of several cracked configurations. Two approaches have been selected for the fracture analyses: on one hand, the global approach based on the concept of crack driving force J and on the other hand, a local approach of ductile fracture. In this approach the crack initiation and growth are modelized by the nucleation, growth and coalescence of cavities in front of the crack tip. The model selected in this study estimates only the growth of the cavities using the RICE and TRACEY relationship. The present study deals with a benchmark on computational simulation of CT fracture experiments using three computer codes : ALIBABA developed by EDF the CEA's code CASTEM 2000 and the FRAMATOME's code SYSTUS. The paper is split into three parts. At first, the authors present the experimental procedure for high temperature toughness testing of two CT specimens taken from a welded pipe, characteristic of pressurized water reactor primary piping. Secondly, considerations are outlined about the Finite Element analysis and the application procedure. A detailed description is given on boundary and loading conditions, on the mesh characteristics, on the numerical scheme involved and on the void growth computation. Finally, the comparisons between numerical and experimental results are presented up to the crack initiation, the tearing process being not taken into account in the present study. The variations of J and of the local variables used to estimate the damage around the crack tip (triaxiality and hydrostatic stresses, plastic deformations, void growth ...) are computed as a function of the increasing load

  20. Weld controller for automated nuclear service welding

    International Nuclear Information System (INIS)

    Barfield, K.L.; Strubhar, P.M.; Green, D.I.

    1995-01-01

    B and W Nuclear Technologies (BWNT) uses many different types of weld heads for automated welding in the commercial nuclear service industry. Some weld heads are purchased as standard items, while others are custom designed and fabricated by BWNT requiring synchronized multiaxis motion control. BWNT recently completed a development program to build a common weld controller that interfaces to all types of weld heads used by BWNT. Their goal was to construct a system that had the flexibility to add different modules to increase the capability of the controller as different application needs become necessary. The benefits from having a common controller are listed. This presentation explains the weld controller system and the types of applications to which it has been applied

  1. Low heat input welding of nickel superalloy GTD-111 with Inconel 625 filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Athiroj, Athittaya; Wangyao, Panyawat; Hartung, Fritz; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2018-03-01

    GTD-111 precipitation-strengthened nickel-based superalloy is widely used in blades of gas turbine engines which operate at high temperature and in a hot localized corrosion atmosphere. After long-term exposure to high temperature, γ' precipitate is known to exhibit catastrophic changes in size and distribution which cause deterioration of its properties and failure of the component. In this study, a damaged blade removed from a land-based gas turbine generator was subjected to nonpre-heat-treated GTAW and laser welding repair with various welding powers in the range of 135 to 295 J x mm{sup -1}, followed by post-weld heat treatment (PWHT) at 1473 K for 7200 s and strain aging at 1118 K for 86 400 s. Results show no significant relationship between welding powers, size and area fraction of the γ' precipitate in the fcc γ matrix in both GTAW and laser-welded specimens. The final γ' precipitate size and distribution depend mainly on PWHT parameters as γ' precipitates in all GTAW and laser welded specimens showed similar size and area fraction independently of the heat input from welding. Unmixed zones are observed in all laser welding specimens which may cause preferential weld corrosion during service. Microcrack occurrence due to welding and PWHT processes is also discussed.

  2. Hydrogen Cracking in Gas Tungsten Arc Welding of an AISI Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, P.; Unigovski, Ya.; Shneck, R.

    The effects of in situ cathodic charging on the tensile properties and susceptibility to cracking of an AISI type 321 stainless steel, welded by the gas tungsten arc welding (GTAW) process, was studied by various treatments. Appearance of delta-ferrite phase in the as-welded steels in our tested conditions was observed with discontinuous grain boundaries (M23C6) and a dense distribution of metal carbides MC ((Ti, Nb)C), which precipitated in the matrix. Shielding gas rates changes the mechanical properties of the welds. Ultimate tensile strength and ductility are increases with the resistance to the environments related the increase of the supplied shielding inert gas rates. Charged specimens, caused mainly in decreases in the ductility of welded specimens. However, more severe decrease in ductility was obtained after post weld heat treatment (PWHT). The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited massive transgranular regions. Both types of specimen demonstrated narrow brittle zones at the sides of the fracture surface and ductile micro-void coalescences in the middle. Ferrite δ was form after welding with high density of dislocation structures and stacking faults formation and the thin stacking fault plates with e-martensite phase were typically found in the austenitic matrix after the cathodical charging process.

  3. Friction Stir Weld Restart+Reweld Repair Allowables

    Science.gov (United States)

    Clifton, Andrew

    2008-01-01

    A friction stir weld (FSW) repair method has been developed and successfully implemented on Al 2195 plate material for the Space Shuttle External Fuel Tank (ET). The method includes restarting the friction stir weld in the termination hole of the original weld followed by two reweld passes. Room temperature and cryogenic temperature mechanical properties exceeded minimum FSW design strength and compared well with the development data. Simulated service test results also compared closely to historical data for initial FSW, confirming no change to the critical flaw size or inspection requirements for the repaired weld. Testing of VPPA fusion/FSW intersection weld specimens exhibited acceptable strength and exceeded the minimum design value. Porosity, when present at the intersection was on the root side toe of the fusion weld, the "worst case" being 0.7 inch long. While such porosity may be removed by sanding, this "worst case" porosity condition was tested "as is" and demonstrated that porosity did not negatively affect the strength of the intersection weld. Large, 15-inch "wide panels" FSW repair welds were tested to demonstrate strength and evaluate residual stresses using photo stress analysis. All results exceeded design minimums, and photo stress analysis showed no significant stress gradients due to the presence of the restart and multi-pass FSW repair weld.

  4. Electron beam welding of high-purity copper accelerator cells

    International Nuclear Information System (INIS)

    Delis, K.; Haas, H.; Schlebusch, P.; Sigismund, E.

    1986-01-01

    The operating conditions of accelerator cells require high thermal conductivity, low gas release in the ultrahigh vacuum, low content of low-melting metals and an extremely good surface quality. In order to meet these requirements, high-purity copper (OFHC, Grade 1, according to ASTM B 170-82 and extra specifications) is used as structural material. The prefabricated components of the accelerator cells (noses, jackets, flanges) are joined by electron beam welding, the weld seam being assessed on the basis of the same criteria as the base material. The welding procedures required depend, first, on the material and, secondly, on the geometries involved. Therefore experimental welds were made first on standardized specimens in order to study the behaviour of the material during electron beam welding and the influence of parameter variations. The welded joints of the cell design were planned on the basis of these results. Seam configuration, welding procedures and the parameters were optimized on components of original geometry. The experiments have shown that high-quality joints of this grade of copper can be produced by the electron beam welding process, if careful planning and preparation of the seams and adequate containment of the welding pool are assured. (orig.)

  5. Torque strength of an endplate welding due to process parameters using a fuel assembling welder

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and end plug, this welding part is connected with the safety of nuclear fuel rods. Endplug-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and endplug is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and endplug. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a bundle fuel welder to measure and analyze the torque of an endplug-endplate welding. The torque of a weldment between an endplug and endplate was measured and analyzed with the welding time. The weldability of a weldment between an endplug and endplate was investigated by a metallographic examination.

  6. An Experimental Investigation on APR1400 Penetration Weld Failure by Metallic Melt

    International Nuclear Information System (INIS)

    An, Sang Mo; Ha, Kwang Soon; Kim, Hwan Yeol

    2014-01-01

    The penetrations are considered as the most vulnerable parts with respect to the reactor vessel failure when a core melt severe accident occurs and the corium reaches the lower head. Penetration tube failure modes can be divided into two categories; tube ejection out of the vessel lower head and rupture of the penetration tube outside the vessel. Tube ejection begins with degrading the penetration tube weld strength to zero as the weld is exposed to temperatures as high as the weld melting temperature, which is called weld failure, and then overcoming any binding force in the hole in the vessel wall that results from differential thermal expansion of the tube and vessel wall. Tube rupture assumes that the debris bed has melted the instrument tube inside the reactor and melt migrates down into the tube to a location outside the vessel wall where a pressure rupture can occur, thus breaching the pressure boundary. In the present paper, we have a focus on the tube ejection failure mode, specifically on the APR1400 weld failure by direct contact with a metallic melt. The objective is to investigate experimentally the ablation kinetics of an APR1400 penetration weld during the interactions with a metallic melt and to suggest the modification of the existing weld failure model. This paper involves the interaction experiments of two different metallic melts (metallic corium and stainless steel melts) with a weld specimen, and rough estimation of weld failure time. The interaction experiments between the metallic melts and an APR1400 penetration weld were performed to investigate the ablation kinetics of the penetration weld. Metallic corium and stainless steel melts were generated using an induction heating technique and interacted with a penetration weld specimen. The ablation rate of the weld specimen showed a range from 0.109 to 0..244 mm/s and thus the APR1400 penetration weld was estimated to be failed at hundreds of times after the interaction with the melt

  7. The characteristics of laser welded magnesium alloy using silver nanoparticles as insert material

    International Nuclear Information System (INIS)

    Ishak, M.; Maekawa, K.; Yamasaki, K.

    2012-01-01

    Highlights: ► Ag nanoparticles are used as insert material for welding Mg alloy with laser. ► We examine the microstructure and mechanical properties of welded Mg alloys. ► Nananoparticle promote grain refinement to the weld structure. ► Finer nanoparticle produces high weld efficiency and mechanical properties. - Abstract: This paper describes the characteristics of the laser welding of thin-sheet magnesium alloys using silver (Ag) nanoparticles as an insert material. The experiment was conducted using nanoparticles with 5 nm and 100 nm diameters that were welded with a Nd:YAG laser. The microstructure and mechanical properties of the specimens welded using inserts with different sizes of nanoparticles and without an insert material, were examined. Electron probe micro-analyzer (EPMA) analysis was conducted to confirm the existence of Ag in the welded area. The introduction of the Ag nanoparticle insert promoted large area of fine grain and broadened the acceptable range of scanning speed parameters compared to welds without an insert. Welds with 5 nm nanoparticles yielded the highest fracture load of up to 818 N while the lowest fracture load was found for weld specimens with 100 nm nanoparticles. This lower fracture load was due to larger voids and a smaller throat length, which contributed to a lower fracture load when using larger nanoparticles.

  8. Research on fatigue behavior and residual stress of large-scale cruciform welding joint with groove

    International Nuclear Information System (INIS)

    Zhao, Xiaohui; Liu, Yu; Liu, Yong; Gao, Yuan

    2014-01-01

    Highlights: • The fatigue behavior of the large-scale cruciform welding joint with groove was studied. • The longitudinal residual stress of the large-scale cruciform welding joint was tested by contour method. • The fatigue fracture mechanism of the large-scale cruciform welding joint with groove was analyzed. - Abstract: Fatigue fracture behavior of the 30 mm thick Q460C-Z steel cruciform welded joint with groove was investigated. The fatigue test results indicated that fatigue strength of 30 mm thick Q460C-Z steel cruciform welded joint with groove can reach fatigue level of 80 MPa (FAT80). Fatigue crack source of the failure specimen initiated from weld toe. Meanwhile, the microcrack was also found in the fusion zones of the fatigue failure specimen, which was caused by weld quality and weld metal integrity resulting from the multi-pass welds. Two-dimensional map of the longitudinal residual stress of 30 mm thick Q460C-Z steel cruciform welded joint with groove was obtained by using the contour method. The stress nephogram of Two-dimensional map indicated that longitudinal residual stress in the welding center is the largest

  9. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

  10. Development of an End-plug Welding Technology for an Instrumented Fuel Irradiation Test

    International Nuclear Information System (INIS)

    Kim, Soo Sung; Lee, Chul Yong; Shin, Yoon Taek; Choo, Kee Nam

    2010-01-01

    The irradiation test of end-plug specimens was planned for the evaluation of nuclear fuels performance. To establish the fabrication process, and for satisfying the requirements of the irradiation test, an orbital-GTA weld machine for the specimens of the dual rods was developed, and the preliminary welding experiments for optimizing the process conditions of the specimens of the dual rods were performed. Dual rods with a 9.5mm diameter and a 0.6mm wall thickness of the cladding tubes and end-plugs have been used and the optimum conditions of the pin-hole welding have also been selected. This paper describes the experimental results of the GTA welds of the specimens of the dual rods and the metallography examinations of the GTA welded specimens for various welding conditions for the instrumented fuel irradiation test. These investigations satisfied the requirements of the instrumented irradiation test and the GTA welds for the specimens of the dual rods at the HANARO research reactor

  11. Does pattern-welding make Anglo-Saxon swords stronger?

    DEFF Research Database (Denmark)

    Birch, Thomas

    2013-01-01

    to assess whether the technique affects mechanical properties, this experimental study compared pattern-welded and plain forged blanks in a series of material tests. Specimens were subject to tensile, Charpy and Vickers diamond hardness testing. This was to investigate the relative strength, ductility......The purpose of pattern-welding, used for the construction of some Anglo-Saxon swords, has yet to be fully resolved. One suggestion is that the technique enhanced the mechanical properties of a blade. Another explanation is that pattern-welding created a desired aesthetic appearance. In order...... and toughness of pattern-welding. The results were inconclusive, however the study revealed that the fracture performance of pattern-welding may relate to its use....

  12. Molecular detection and confirmation of Neisseria gonorrhoeae in urogenital and extragenital specimens using the Abbott CT/NG RealTime assay and an in-house assay targeting the porA pseudogene.

    LENUS (Irish Health Repository)

    Walsh, A

    2011-04-01

    Culture for detection of Neisseria gonorrhoeae (NG) is being replaced by molecular assays, but difficulties are observed with false positive and negatives results, especially for extragenital samples. This study evaluates the Abbott CT\\/NG Real-Time assay and a real-time porA pseudogene assay. Samples (n = 600) from a mixed prevalence Irish population include 164 male urines with corresponding urethral swabs, 58 endocervical swabs, 173 male pharyngeal swabs, 205 male rectal swabs, 36 NG clinical isolates and 26 commensal Neisseria species isolates. There was a 100% concordance between the Abbott CT\\/NG Real-Time and the porA assay. The positivity rate was 1.2%, 1.7%, 8.1% and 5.8% for FVU\\/urethral swabs, endocervical, pharyngeal and rectal swabs, respectively. These results were compared to culture and discrepancies were found with nine pharyngeal and three rectal swabs. Seven of the 12 discrepant positive samples were sequenced and were confirmed "true positives". The sensitivity and specificity of the molecular assays was 100%. The sensitivity of the culture-based testing was 100% for urogenital samples but 36% and 75% for pharyngeal and rectal swabs, respectively. The combined Abbott CT\\/NG and porA assays provide a valuable alternative to culture and also generate a significant increase in the diagnosis of pharyngeal and rectal NG infection.

  13. Nondestructive testing: welding industry

    International Nuclear Information System (INIS)

    Raj, Baldev; Subramanian, C.V.

    1992-01-01

    This chapter highlights various conventional and advanced nondestructive testing (NDT) techniques that have been used for weld evaluation. Welding Codes and Standards of International and National organisations that have been followed in India for various weld evaluation purposes are also included. The chapter also emphasises the importance of NDT by way of a few case studies that have been carried out on important critical welded components. (author). 12 refs., 17 figs., 1 appendix

  14. Plasma spot welding of ferritic stainless steels

    Directory of Open Access Journals (Sweden)

    Lešnjak, A.

    2002-06-01

    Full Text Available Plasma spot welding of ferritic stainless steels is studied. The study was focused on welding parameters, plasma and shielding gases and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared. Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas, i.e., a 98 % Ar/2 % H 2 gas mixture. Tension-shear strength of plasma-spot welded joints was compared to that of resistance-spot welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a larger weld spot diameter of the former. Strength of both types of welded joints is approximately the same.

    El artículo describe el proceso de soldeo de aceros inoxidables ferríticos por puntos con plasma. La investigación se centró en el establecimiento de los parámetros óptimos de la soldadura, la definición del gas de plasma y de protección más adecuado, así como del equipo óptimo para la realización de la soldadura. Las uniones de láminas de aceros inoxidables ferríticos de 0,8 mm de espesor, soldadas a solape por puntos con plasma, se inspeccionaron visualmente y se ensayaron mecánicamente mediante el ensayo de cizalladura por tracción. Se realizaron macro pulidos. Los resultados de la investigación demostraron que la solución más adecuada para el soldeo por puntos con plasma es elegir el mismo gas de plasma que de protección. Es decir, una mezcla de 98 % de argón y 2 % de hidrógeno. La resistencia a la cizalladura por tracción de las uniones soldadas por puntos con plasma fue comparada con la resistencia de las uniones soldadas por resistencia por puntos. Se llegó a la conclusión de que las uniones soldadas por resistencia soportan una carga algo mayor que la uniones

  15. The influence of low dose irradiation on the creep properties of type 316 welds

    International Nuclear Information System (INIS)

    Marshall, P.; Steeds, J.W.; Lin, Y.P.; Finlan, G.T.

    1987-01-01

    Fully instrumented creep and stress rupture tests have been performed at 873K for times up to 20,000h on a series of type 316 steel/17Cr 8Ni 2Mo weld metal specimens in the unirradiated and thermal neutron irradiated conditions. The specimens tested included all weld metal longitudinal and transverse composites in the as-welded condition and following a stress relief heat treatment of 10h at 1075K. Simulated heat affected zone (HAZ) specimens were also tested. Analysis of the creep results combined with metallography, autoradiography and TEM established that the decrease in properties of irradiated samples is caused by an increasing secondary strain rate due to enhanced helium induced grain boundary fracture of the simulated HAZ and enhanced interdendritic fracture in the weld metal. Implications of strength reductions on the design of welded structures subjected to thermal irradiation are briefly assessed. (author)

  16. Fatigue behaviour of 304L steel welded structures: influence of residual stresses and surface mechanical finishing

    International Nuclear Information System (INIS)

    Magnier-Monin, L.

    2007-12-01

    This study focuses on the influence of residual stresses and surface mechanical finishing on lifetime of stainless steel 304L welded structures. Residual stresses are determined on specific specimens of three types: base-metal, as-welded and ground-welded specimens. Each type is submitted to fatigue tests in order to assess the influence of these parameters on the lifetime, and to determine their evolution. The experiments show that an important surface stress concentration is located in the weld root of as-welded structures, which has a negative effect on the fatigue life. The grinding operation generates high-level surface residual stresses but the lifetime is higher thanks to the reduction of the notch effect. The fatigue test results are compared to the nuclear industry best-fit S-N curves. This enables the determination of correction factors related to fatigue test results of polished specimens, and to assess the lifetime of structures. (author)

  17. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  18. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

    This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

  19. Underwater welding of steel

    International Nuclear Information System (INIS)

    Ibarra, S.; Olson, D.L.

    1992-01-01

    A fundamental basis to understand the behavior of wet underwater welding of steel is introduced. Both the pyrometallurgical and physical metallurgy concepts are discussed. Modifications of welding consumables and practice are suggested. This chapter promotes further contributions of meatllurgical research to improve and promote wet underwater welding. (orig.)

  20. Welding Over Paint Primer

    National Research Council Canada - National Science Library

    Johnson, Kevin S; Liu, Stephen; Olson, David L

    1998-01-01

    .... According to the hydrogen-oxygen and }hydrogen-fluorine equilibrium considerations, an increase in the partial pressure of oxygen or fluorine could decrease the partial pressure of hydrogen within the welding arc. Consequently, a welding consumable that contains chemical ingredients of high oxygen and fluorine potential would be capable of minimizing hydrogen pick-up in the weld pool.

  1. Fracture toughness testing of pipeline girth welds

    Energy Technology Data Exchange (ETDEWEB)

    Shen, G.; Gianetto, J.A.; Bouchard, R.; Bowker, J.T.; Tyson, W.R.

    2005-06-01

    This paper reviewed the fracture toughness test standards for pipeline girth welds outlined in CSA Z662-03, Annex K as well as the referenced testing standards BS 7448 and ASTM Standard E 1290. The requirements outlined in API 1104, appendix A were also reviewed given its application throughout the world. Crack tip opening displacement (CTOD) tests were conducted on a manual shielded-metal-arc weld (SMAW) that was prepared in a high strength X80 pipeline steel. Another girth weld test consisted of a mechanized gas metal arc weld (GMAW), but only the results for the SMAW were presented in this paper. Two tensile specimens were machined parallel to the pipe axis from the base metal of the X80 pipe used in preparing the pipeline girth welds. The tensile specimens from the pipe base metal and weld metal were tested at 20 degrees C. The yield strength at the CTOD test temperature was estimated by using the yield strength-temperature relationship given in BS 7448. The experimental results obtained by applying the two testing standards were compared. The intent was to identify the differences between these two standards and their influence on test results. The authors discussed critical issues for the fracture toughness tests, such as weld position and notch orientation, circumferential sampling location, residual stress and its modification, crack length measurement and the equations used to evaluate CTOD. The variation of strength and toughness with clock position around the circumference of the girth welds was also discussed. It was concluded that for a high-strength material, local compression may be needed to create a uniform fatigue crack front. For deep-cracked specimens, the maximum allowable difference of the measured fatigue crack length varies significantly between ASTM E 1290-02 and BS 7448 by a factor of about 1 to 3 for ASTM E 1290 and 3 to 15 for BS 7448. The CTOD calculated according to ASTM E 1290-02 and according to BS 7448 can also differ substantially

  2. Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam of Greifswald unit 8

    International Nuclear Information System (INIS)

    Viehrig, Hans-Werner; Schuhknecht, Jan

    2008-01-01

    WWER-440 second generation (V-213) reactor pressure vessels (RPV) were produced by IZHORA in Russia and by SKODA in the former Czechoslovakia. The surveillance Charpy-V and fracture mechanics SE(B) specimens of both producers have different orientations. The main difference is the crack extension direction which is through the RPV thickness and circumferential for ISHORA and SKODA RPV, respectively. In particular for the investigation of weld metal from multilayer submerged welding seams the crack extension direction is of importance. Depending on the crack extension direction in the specimen there are different welding beads or a uniform structure along the crack front. The specimen orientation becomes more important when the fracture toughness of the weld metal is directly determined on surveillance specimens according to the Master Curve (MC) approach as standardised in the ASTM Standard Test Method E1921. This approach was applied on weld metal of the RPV beltline welding seam of Greifswald Unit 8 RPV. Charpy size SE(B) specimens from 13 locations equally spaced over the thickness of the welding seam were tested. The specimens are in TL and TS orientation. The fracture toughness values measured on the SE(B) specimens with both orientations follow the course of the MC. Nearly all values lie within the fracture toughness curves for 5% and 95% fracture probability. There is a strong variation of the reference temperature T 0 though the thickness of the welding seam, which can be explained with structural differences. The scatter is more pronounced for the TS SE(B) specimens. It can be shown that specimens with TS and TL orientation in the welding seam have a differentiating and integrating behaviour, respectively. The statistical assumptions behind the MC approach are valid for both specimen orientations even if the structure is not uniform along the crack front. By comparison crack extension, JR, curves measured on SE(B) specimens with TL and TS orientation show

  3. Electrostimulated recovery of welded joint durability: experiment and model

    International Nuclear Information System (INIS)

    Semakin, E.V.; Chirakadze, D.Z.; Tsellermaer, V.Ya.; Gromov, V.E.; Sosnin, O.V.

    1997-01-01

    The possibility to increase the durability of welded joints operating under conditions of low cycle fatigue is shown to be brought about using electric current pulses. Experimental method of recovery of operational capability is demonstrated on welded joints of tool steels R6M5 and 40Kh/ The onset of critical stage of fatigue in the welded joint was determined by ultrasonic testing. Then the specimens were treated with 20 Hz electric pulses with amplitude of 250 MA/M 2 for 100 μs. Such treatment resulted in an increase of time to fracture. The phenomenological model of the process is proposed

  4. Fracture toughness properties of similar and dissimilar electron beam welds

    International Nuclear Information System (INIS)

    Kocak, M.; Junghans, E.

    1994-01-01

    The weldability aspects, tensile and Crack Tip Opening Displacement (CTOD) toughness properties of 9Cr1MoNbV (P91) martensitic steel with austenitic 316L steel were evaluated for electron beam (EB) welds on 35 mm thick pates. The effects of mechanical heterogeneity (mis-matching) at the vicinity of the crack tip of dissimilar three point bend specimens on the CTOD fracture toughness values was also discussed. The CTOD tests were performed on similar and dissimilar EB welds of austenitic and tempered martensitic P91 steels at room temperature. Dilution of austenitic with martensitic steel resulted in predominantly martensitic EB weld metal, exhibiting rather high yield strength and hardness. Nevertheless, the weld metal produced high CTOD toughness values due to the beneficial effect of the lower strength austenitic steel part of the specimen in which crack deviation occured (mis-match effect). The coarse grained HAZ of the P91 steel side exhibits extremely poor CTOD toughness properties in the as-welded condition at room temperature. The CTOD values obtained are believed to be representing the intrinsic property of this zone since the distance of the crack tip to the weaker austenitic steel part of the SENB specimens was too large to cause an effective stress relaxation at the crack tip. Further post weld heat treatment at 750 C for two hours improved the CTOD toughness marginally. (orig.)

  5. Residual stress investigation of copper plate and canister EB-Welds Complementary Results

    International Nuclear Information System (INIS)

    Gripenberg, H.

    2009-03-01

    The residual stresses in copper as induced by EB-welding were studied by specimens where the weld had two configurations: either a linear or a circumferential weld. This report contains the residual stress measurements of two plates, containing linear welds, and the full-scale copper lid specimen to which a hollow cylinder section had been joined by a circumferential EB-weld. The residual stress state of the EB-welded copper specimens was investigated by X-ray diffraction (XRD), hole drilling (HD) ring core (RC) and contour method (CM). Three specimens, canister XK010 and plates X251 and X252, were subjected to a thorough study aiming at quantitative determination of the residual stress state in and around the EB-welds using XRD for surface and HD and RC for spatial stress analysis. The CM maps one stress component over a whole cross section. The surface residual stresses measured by XRD represent the machined condition of the copper material. The XRD study showed that the stress changes towards compression close to the weld in the hollow cylinder, which indicates shrinkage in the hoop direction. According to the same analogy, the shrinkage in the axial direction is much smaller. The HD measurements showed that the stress state in the base material is bi-axial and, in terms of von Mises stress, 50 MPa for the plates and 20 MPa for the cylinder part of the canister. The stress state in the EB-welds of all specimens differs clearly from the stress state in the base material being more tensile, with higher magnitudes of von Mises stress in the plate than in the canister welds. The HD and RC results were obtained using linear elastic theory. The RC measurements showed that the maximum principal stress in the BM is close to zero near the surface and it becomes slightly tensile, 10 MPa, deeper under the surface. Welding pushed the general stress state towards tension with the maximum principal stress reaching 50 MPa, deeper than 5 mm below the surface in the weld. The

  6. The effect of neutron irradiation on the mechanical properties of welded zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D G

    1962-07-15

    Zircaloy-2 tensile specimens, subsize impact bars and representative spigot welds were subjected to three NRX cycles in the X-5 loop. Average loop temperature was 260{sup o}C over the three cycles. One group of tensile specimens was heat-treated in vacuum at 900{sup o}C for 40 minutes, another group contained welded areas in the centre of the gauge length and a third group was hydrided after welding. Notches of the impact specimens were located in the fusion zone of the weld, Spigot welds were made on autoclaved and unautoclaved simulated production assemblies. The transition temperature of Zircaloy-2 increased appreciably upon welding. This was accompanied by a decrease in absorbed energy values for all temperatures between 0{sup o} and 300{sup o}C. Neutron irradiation had no effect on the impact properties of welded. Zircaloy-2. Welding decreased the uniform and total elongation at room temperature and at 260{sup o}C, and increased the 260{sup o}C PL, YS and UTS. Hydriding to a nominal 100 ppm hydrogen had no effect on the unirradiated tensile properties at either test temperature. The heat treatment decreased the strength properties but did not affect the ductility. Neutron irradiation increased the YS of the welded and hydrided material by 20% and the heat treated YS by 40%. Irradiation also increased the 260{sup o}C strength properties of the as-welded material. It was found that the unautoclaved spigot welds had a generally higher tensile strength than the autoclaved and welded specimens. For specimens welded in either condition, the outer welds of the 19-element bundle had a lower average breaking load than the inner welds. Neutron irradiation had no effect on the tensile strength of these welds. It was also demonstrated that a cup-and-cone type of fracture could be produced in a bend test. These fractures were similar to those observed in irradiated fuel bundles which had been damaged during transfer operations. A large amount of scatter rendered some

  7. Designing of CK45 carbon steel and AISI 304 stainless steel dissimilar welds

    OpenAIRE

    Pouraliakbar,Hesam; Hamedi,Mohsen; Kokabi,Amir Hossein; Nazari,Ali

    2014-01-01

    Gas tungsten arc welding of CK45 and AISI304 stainless steel was performed through preparation of different types of samples using ER308L and ERNi-1 wires. Welded samples were studied by different techniques including optical metallography, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction, hardness measurements and impact test. It was observed that in the buttered specimen, the structure of the weld metal was completely austenitic wh...

  8. Mechanical behaviour of cracked welded structures including mismatch effect

    International Nuclear Information System (INIS)

    Hornet, P.

    2002-01-01

    The most important parameters for predicting more precisely the fracture behaviour of welded structures have been identified. In particular, the plasticity development at the crack tip in the ligament appeared as a major parameter to evaluate the yield load of such a complex structure. In this way defect assessments procedures have been developed or modified to take into account the mismatch effect that is to say the mechanical properties of the different material constituting the weld joint. This paper is a synthesis of the work done in the past at Electricite de France on this topic in regards with other work done in France or around the World. The most important parameters which control the plasticity development at the crack tip and so mainly influence the fracture behaviour of welded structures are underlined: the mismatch ratio (weld to base metal yield strength ratio), the mismatch ratio (weld to base metal yield strength ratio), the ligament size and the weld width. Moreover, commonly used fracture toughness testing procedures developed in case of homogeneous specimens cannot be used in a straight forward manner and so has to be modified to take into account the mismatch effect. Number or defect assessment procedures taking into account the mismatch effect by considering the yield load of the welded structure are shortly described. Then, the 'Equivalent Material Method' developed at EDF which allows a good prediction of the applied J-Integral at the crack tip is more detailed. This procedure includes not only both weld and base metal yield strength, the structure geometry, the crack size and the weld dimension using the yield load of the real structures but also includes the effect of both weld and base metal strain hardening exponents. Some validations of this method are proposed. Finally, the ability of finite element modelling to predict the behaviour of such welded structures is demonstrated by modelling real experiments: crack located in the middle of

  9. Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L. Wood

    Directory of Open Access Journals (Sweden)

    Jussi Ruponen

    2015-04-01

    Full Text Available The purpose of this work was to determine the optimal welding time for linear friction welding of birch (Betula pendula L. wood while keeping the other parameters constant and at similar levels compared to other species in a similar density range. Specimens with dimensions of 20 × 5 × 150 mm3 were welded together, and the influence of welding time (2.5, 3.0, 3.5, and 4.0 s on the mechanical properties of the specimens was determined. The studies included a tensile-shear strength test as well as visual estimation of wood failure percentage (WFP. Additionally, X-ray microtomographic imaging was used to investigate and characterise the bond line properties as a non-destructive testing method. The highest mean tensile-shear strength, 7.9 MPa, was reached with a welding time of 3.5 s. Generally, all four result groups showed high, yet decreasing proportional standard deviations as the welding time increased. X-ray microtomographic images and analysis express the heterogeneity of the weld line clearly as well. According to the averaged group-wise results, WFP and tensile-shear strength correlated positively with an R2 of 0.93. An extrapolation of WFP to 65% totals a tensile-shear strength of 10.6 MPa, corresponding to four common adhesive bonds determined for beech.

  10. Orbital welding technique

    International Nuclear Information System (INIS)

    Hoeschen, W.

    2003-01-01

    The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [de

  11. Statistical analyses of fracture toughness results for two irradiated high-copper welds

    International Nuclear Information System (INIS)

    Nanstad, R.K.; McCabe, D.E.; Haggag, F.M.; Bowman, K.O.; Downing, D.J.

    1990-01-01

    The objectives of the Heavy-Section Steel Irradiation Program Fifth Irradiation Series were to determine the effects of neutron irradiation on the transition temperature shift and the shape of the K Ic curve described in Sect. 6 of the ASME Boiler and Pressure Vessel Code. Two submerged-arc welds with copper contents of 0.23 and 0.31% were commercially fabricated in 215-mm-thick plates. Charpy V-notch (CVN) impact, tensile, drop-weight, and compact specimens up to 203.2 mm thick [1T, 2T, 4T, 6T, and 8T C(T)] were tested to provide a large data base for unirradiated material. Similar specimens with compacts up to 4T were irradiated at about 288 degrees C to a mean fluence of about 1.5 x 10 19 neutrons/cm 2 (>1 MeV) in the Oak Ridge Research Reactor. Both linear-elastic and elastic-plastic fracture mechanics methods were used to analyze all cleavage fracture results and local cleavage instabilities (pop-ins). Evaluation of the results showed that the cleavage fracture toughness values determined at initial pop-ins fall within the same scatter band as the values from failed specimens; thus, they were included in the data base for analysis (all data are designated K Jc )

  12. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3...... transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ......Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking...

  13. Metallurgical and mechanical characterization of a submerged arc welded joint in a 316 type stainless steel

    International Nuclear Information System (INIS)

    Piatti, G.; Vedani, M.

    1990-01-01

    The tensile (deformation and fracture) behaviour of a multipass submerged arc welded joint Type 316 stainless steel is investigated by tests at room temperature and at 400 0 C on all-weld metal and transverse to weld (composite) specimens as well as by microstructural and compositional analyses (optical, scanning electron and transmission electron microscopy). The as-deposited metal is characterised by a systematic variation in the tensile properties across the thickness with the higher strength and the lower ductility in the weld centre. These variations are related to material variability (mainly in dislocation density) because of local dissimilarities in thermal and mechanical histories occurring during the welding process. However, the material variability in the fusion zone, although important is not so large in the present weld and it does not influence the tensile properties of the weld as a whole. Moreover, the tensile behaviour concerning the transverse to weld specimens is characterized by a supporting effect from the higher yield strength material zone (fusion zone) to the lower yield strength material zone (parent metal) justified by the different contribution of the parent metal and of the weld-deposit metal to the integral plastic strain of the specimens. (author)

  14. Effect of multiple repairs in girth welds of pipelines on the mechanical properties

    International Nuclear Information System (INIS)

    Vega, O.E.; Hallen, J.M.; Villagomez, A.; Contreras, A.

    2008-01-01

    This work presents the results of multiple weld repairs in the same area in seamless API X-52 microalloyed steel pipe. Four conditions of shielded metal arc welding repairs and one as-welded specimen of the girth weld were characterized to determine changes in the microstructure, grain size in the heat affected zone, and to evaluate their effect on the mechanical properties of the weld joints. The mechanical properties by means of tension tests, Charpy-V impact resistance and Vickers hardness of the welds were analyzed. The results indicate that significant changes are not generated in the microstructural constituents of the heat affected zone. Grain growth in the heat affected zone at the specimen mid-thickness with the number of repairs was observed. Tensile strength of the weld joints meets the requirement of the API 1104 standard even after the fourth weld repair. Significant reduction in Charpy-V impact resistance with the number of weld repairs was found when the notch location was in the intersection of the fusion line with the specimen mid-thickness. A significant increase in the Vickers hardness of the heat affected zone occurred after the first repair and a gradual decrease in the Vickers hardness occurred as the number of repairs increases

  15. Modification of creep and low cycle fatigue behaviour induced by welding

    Directory of Open Access Journals (Sweden)

    A. Carofalo

    2014-10-01

    Full Text Available In this work, the mechanical properties of Waspaloy superalloy have been evaluated in case of welded repaired material and compared to base material. Test program considered flat specimens on base and TIG welded material subjected to static, low-cycle fatigue and creep test at different temperatures. Results of uniaxial tensile tests showed that the presence of welded material in the gage length specimen does not have a relevant influence on yield strength and UTS. However, elongation at failure of TIG material was reduced with respect to the base material. Moreover, low-cycle fatigue properties have been determined carrying out tests at different temperature (room temperature RT and 538°C in both base and TIG welded material. Welded material showed an increase of the data scatter and lower fatigue strength, which was anyway not excessive in comparison with base material. During test, all the hysteresis cycles were recorded in order to evaluate the trend of elastic modulus and hysteresis area against the number of cycles. A clear correlation between hysteresis and fatigue life was found. Finally, creep test carried out on a limited number of specimens allowed establishing some changes about the creep rate and time to failure of base and welded material. TIG welded specimen showed a lower time to reach a fixed strain or failure when a low stress level is applied. In all cases, creep behaviour of welded material is characterized by the absence of the tertiary creep.

  16. Corrosion fatigue crack growth of pressure vessel welds in PWR environment

    International Nuclear Information System (INIS)

    Bamford, W.H.; Ceschini, L.J.; Moon, D.M.

    1983-01-01

    The fatigue crack growth rate behavior of several pressure vessel steel welds in PWR environment is discussed. The behavior is compared with associated heat-affected zone behavior, and with comparable base metal results. The welds show different degrees of susceptibility to the environmental influence, and this is discussed in some detail, along with fractographic observations on the tested specimens

  17. 49 CFR 178.57 - Specification 4L welded insulated cylinders.

    Science.gov (United States)

    2010-10-01

    ... lot of cylinders. The test piece must be welded by the same welding procedure as used on the... conform to requirements of ASTM Standard E 23. The test piece, as well as the handling tongs, must be... than six seconds. (vii) The impact properties of each set of impact specimens may not be less than the...

  18. Effect of Welding Parameters on Microstructure and Mechanical Properties of Cast Fe-40Al Alloy

    Directory of Open Access Journals (Sweden)

    Osman Torun

    2016-09-01

    Full Text Available Friction welding of cast Fe-40Al alloy was carried out at 1000 rmp for various friction times, friction pressures, and forging pressures. The microstructures of the interface of welded samples were analyzed by optical and scanning electron microscopy (SEM. Micrographs demonstrated that excellent welding formed continuously along the interface, except for samples welded for 3 s. Chemical compositions of the interface of the friction welded samples and of the fractured surface of all the specimens were determined using energy dispersive spectroscopy (EDS. After the welding process, shear tests were applied to the welded samples to determine the shear strength of joints. Test results indicated that the maximum shear strength was 469.5 MPa.

  19. A comparative study of laser beam welding and laser-MIG hybrid welding of Ti-Al-Zr-Fe titanium alloy

    International Nuclear Information System (INIS)

    Li Ruifeng; Li Zhuguo; Zhu Yanyan; Rong Lei

    2011-01-01

    Research highlights: → Ti-Al-Zr-Fe titanium alloy sheets were welded by LBW and LAMIG methods. → LAMIG welded joints have better combination of strength and ductility. → LAMIG welding is proved to be feasible for the production of titanium sheet joints. - Abstract: Ti-Al-Zr-Fe titanium alloy sheets with thickness of 4 mm were welded using laser beam welding (LBW) and laser-MIG hybrid welding (LAMIG) methods. To investigate the influence of the methods difference on the joint properties, optical microscope observation, microhardness measurement and mechanical tests were conducted. Experimental results show that the sheets can be welded at a high speed of 1.8 m/min and power of 8 kW, with no defects such as, surface oxidation, porosity, cracks and lack of penetration in the welding seam. In addition, all tensile test specimens fractured at the parent metal. Compared with the LBW, the LAMIG welding method can produce joints with higher ductility, due to the improvement of seam formation and lower microhardness by employing a low strength TA-10 welding wire. It can be concluded that LAMIG is much more feasible for welding the Ti-Al-Zr-Fe titanium alloy sheets.

  20. Mechanical Behaviour Investigation Of Aluminium Alloy Tailor Welded Blank Developed By Using Friction Stir Welding Technique

    Science.gov (United States)

    Dwi Anggono, Agus; Sugito, Bibit; Hariyanto, Agus; Subroto; Sarjito

    2017-10-01

    The objective on the research was to investigate the mechanical properties and microstructure of tailor welded blank (TWB) made from AA6061-T6 and AA1100 using friction stir welding (FSW) process. Due to the dissimilar mechanical properties of the two aluminium alloys, microhardness test was conducted to measure the hardness distribution across the weld nugget. The mixing of two distinct materials was influenced by tool rotation speed. Therefore, microstructure analysis was carried out to investigate the grain size and shape. The grain size of AA6061-T6 has increased in the heat affected zone (HAZ) while for AA1100 has decreased. In the weld nugget, it has found a hook defects in the dissimilar aluminium joining. By using monotonic tensile load, the different weld line direction was observed with the expansion in tool rotation. The joints failure were consistently on the area of AA1100 series. Furthermore, two specimens were investigated, one through the dissimilar aluminium and the other through similiar material. Inspection of the weld nugget hardness was shown that nonhomogen material intermixing during the stiring process as confirmed by microhardness measurement.

  1. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  2. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    International Nuclear Information System (INIS)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du

    2015-01-01

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  3. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

    2015-02-15

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  4. Application of acoustic emission technique and friction welding for excavator hose nipple

    International Nuclear Information System (INIS)

    Kong, Yu Sik; Lee, Jin Kyung

    2013-01-01

    Friction welding is a very useful joining process to weld metals which have axially symmetric cross section. In this paper, the feasibility of industry application was determined by analyzing the mechanical properties of weld region for a specimen of tube-to-tube shape for excavator hose nipple with friction welding, and optimized welding variables were suggested. In order to accomplish this object, friction heating pressure and friction heating time were selected as the major process variables and the experiment was performed in three levels of each parameter. An acoustic emission(AE) technique was applied to evaluate the optimal friction welding conditions nondestructively. AE parameters of accumulative count and event were analyzed in terms of generating trend of AE signals across the full range of friction weld. The typical waveform and frequency spectrum of AE signals which is generated by friction weld were discussed. From this study the optimal welding variables could be suggested as rotating speed of 1300 rpm, friction heating pressure of 15 MPa, and friction heating time of 10 sec. AE event was a useful parameter to estimate the tensile strength of tube-to tube specimen with friction weld.

  5. Preserve specimens for reproducibility

    Czech Academy of Sciences Publication Activity Database

    Krell, F.-T.; Klimeš, Petr; Rocha, L. A.; Fikáček, M.; Miller, S. E.

    2016-01-01

    Roč. 539, č. 7628 (2016), s. 168 ISSN 0028-0836 Institutional support: RVO:60077344 Keywords : reproducibility * specimen * biodiversity Subject RIV: EH - Ecology, Behaviour Impact factor: 40.137, year: 2016 http://www.nature.com/nature/journal/v539/n7628/full/539168b.html

  6. Experimental modeling of weld thermal cycle of the heat affected zone (HAZ

    Directory of Open Access Journals (Sweden)

    J. Kulhánek

    2016-10-01

    Full Text Available Contribution deals with experimental modeling of quick thermal cycles of metal specimens. In the introduction of contribution will be presented measured graphs of thermal cycle of heat affected zone (HAZ of weld. Next will be presented experimental simulation of measured thermal cycle on the standard specimens, useable for material testing. This approach makes possible to create material structures of heat affected zone of weld, big enough for standard material testing.

  7. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    Directory of Open Access Journals (Sweden)

    Thanee Toomprasen

    2014-06-01

    Full Text Available This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grains. in the welded area. This is the result of friction pressure and upset pressure in the welding process. In addition, the observation result indicated some changes of Ferrite and Pearlite in welded zone. This phase change resulted in the increment of hardness in AISI 4140 at the contact area and adjacent. In part of AISI 1040, the portion of Pearlite and Ferrite are not significantly changed, therefore the value of hardness is almost constant.

  8. A study of fatigue life distribution of butt-welded joints

    International Nuclear Information System (INIS)

    Sakai, Tatsuo; Fujitani, Keizo; Kikuchi, Toshiro; Tanaka, Takao.

    1981-01-01

    Various kinds of welded joints are being used in many structures such as ships, bridges and constructions. It is important in reliability analysis of such structures to clarify the statistical fatigue property of the welded joints. In this study, fatigue tests were carried out on the butt-welded joints of SM50A steel and a theoretical interpretation on the fatigue life distribution was attempted, assuming that a butt-welded joint is composed of a number of sliced specimens with different fatigue strengths. Main results obtained are summarized as follows; (1) The median crack initiation life of the butt-welded joint specimens coincided with that of the sliced specimens, when the crack initiation was defined by a 0.2 mm crack in the sliced specimens or the equivalent state of stress intensity factor in the joint specimens. (2) The distribution of crack initiation lives of the butt-welded joints can be theoretically derived by combining the concept of extreme distribution and the distribution model on the number of fatigue cracks. The theoretical distribution of crack initiation lives of the joints is in good agreement with the general trend of the experimental results. (3) If the distribution of crack initiation lives and the crack growth law are given experimentally, one can obtain analytically the distribution of final fatigue lives. The fatigue life distribution of the sliced specimens can be explained by the theory established in this study. (author)

  9. Welding skate with computerized controls

    Science.gov (United States)

    Wall, W. A., Jr.

    1968-01-01

    New welding skate concept for automatic TIG welding of contoured or double-contoured parts combines lightweight welding apparatus with electrical circuitry which computes the desired torch angle and positions a torch and cold-wire guide angle manipulator.

  10. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  11. Ultrasonic Stir Welding

    Science.gov (United States)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  12. Automatization of welding

    International Nuclear Information System (INIS)

    Iwabuchi, Masashi; Tomita, Jinji; Nishihara, Katsunori.

    1978-01-01

    Automatization of welding is one of the effective measures for securing high degree of quality of nuclear power equipment, as well as for correspondence to the environment at the site of plant. As the latest ones of the automatic welders practically used for welding of nuclear power apparatuses in factories of Toshiba and IHI, those for pipes and lining tanks are described here. The pipe welder performs the battering welding on the inside of pipe end as the so-called IGSCC countermeasure and the succeeding butt welding through the same controller. The lining tank welder is able to perform simultaneous welding of two parallel weld lines on a large thin plate lining tank. Both types of the welders are demonstrating excellent performance at the shops as well as at the plant site. (author)

  13. Explosive welding method for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Rui, E-mail: mr9980@163.com [PLA University of Science and Technology, Nanjing 210007 (China); Wang, Yaohua [PLA University of Science and Technology, Nanjing 210007 (China); Wu, Jihong [Southwestern Institute of Physics, Chengdu 610041 (China); Duan, Mianjun [PLA University of Science and Technology, Nanjing 210007 (China)

    2014-12-15

    Highlights: • Develop a new explosive welding method to fabricate the cooling channel of FW. • Utilize effective energy model to accurately calculate optimal welding parameters. • Provide an efficient way for manufacturing high-ductility hollow structural member. - Abstract: In this study, a new explosive welding method provided an effective way for manufacturing ITER-grade 316L(N)/CuCrZr hollow structural member. The welding parameters (stand-off distance and explosion rate) were calculated respectively using equivalent frontal collision wave model and effective energy model. The welded samples were subject to two step heat treatment cycles (solution annealing and aging). Optical microscopy (OM) and scanning electron microscopy (SEM) were utilized to analyze the microstructure of bonding interface. The mechanical properties of the welded samples were evaluated through microhardness test and tensile test. Moreover, the sealing property of the welded specimens was measured through helium leak test. Microstructural analysis showed that the welded sample using effective energy model had an ideal wavy interface. The results of microhardness test revealed an increase in hardness for both sides near to the bonding interface. And the hardening phenomenon of interface region disappeared after the solution annealing. SEM observation indicated that the samples with the post heat treatments exhibited a ductile fracture with dimple features after tensile test. After the specimens undergo aging strengthening, there was an obvious increase in the strength for all specimens. The helium leak test results have proven that the welded specimens are soundness.

  14. The Effect of Vibration during Friction Stir Welding on Corrosion Behavior, Mechanical Properties, and Machining Characteristics of Stir Zone

    Directory of Open Access Journals (Sweden)

    Sajad Fouladi

    2017-10-01

    Full Text Available Different methods have been applied to refine various characteristics of the zone (or nugget obtained by friction stir welding (FSW. In the current research, joining components are vibrated normal to the weld line during FSW to refine the zone microstructure. This process is described as friction stir vibration welding (FSVW. The effect of FSVW on mechanical properties, corrosion behavior, and machining characteristics of the zone are investigated. Al5052 alloy specimens are welded using FSW and FSVW processes and their different characteristics are compared and discussed. The results show that the strength and ductility of the welded parts increase when the vibration is applied. The outcomes also show that corrosion resistance of the nugget for FSV-welded specimens is lower than FS welded samples, and machining force of the former specimens is higher than the latter ones. These are related to smaller grain size in the zone of FSV-welded specimens compared to FS welded parts. Smaller grain size leads to a greater volume fraction of grain boundaries and, correspondingly, higher strength and hardness, as well as lower corrosion resistance.

  15. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  16. Study of MA Effect on Yield Strength and Ductility of X80 Linepipe Steels Weld

    Science.gov (United States)

    Huda, Nazmul; Lazor, Robert; Gerlich, Adrian P.

    2017-09-01

    Multipass GMAW (Gas Metal Arc Welding) welding was used to join X80 linepipe materials using two weld metals of slightly different compositions. Welding wires with diameters of 0.984 and 0.909 mm were used while applying the same heat input in each pass. The slight difference in the wire diameters resulted in different HAZ microstructures. The microstructures in the doubly reheated HAZ of both welds were found to contain bainite-ferrite. However, etching also revealed a difference in martensite-austenite (MA) fraction in these reheated zones. The MA exhibited twice the hardness of ferrite when measured by nanoindentation. Tensile testing from the reheated zone of both welds revealed a difference in yield strength, tensile strength and elongation of the transverse weld specimens. In the reheated zone of weld A, (produced with a 0.984 mm wire) a higher fraction of MA was observed, which resulted in higher strength but lower elongation compared to weld B. The ductility of weld A was found severely impaired (to nearly half of weld B) due to formation of closely spaced voids around the MA, along with debonding of MA from the matrix, which occurs just above the yield stress.

  17. An assessment of creep strength reduction factors for 316L(N) SS welds

    International Nuclear Information System (INIS)

    Mathew, M.D.; Latha, S.; Rao, K. Bhanu Sankara

    2007-01-01

    Nitrogen-alloyed type 316L stainless steel is the major structural material for the high temperature structural components of prototype fast breeder reactor. For the welding electrode, carbon in the normal range of 0.045-0.055 wt% and nitrogen in the range of 0.06-0.1 wt% are used to provide weld joints with adequate long term creep strength. Characterization of the creep properties of the base metal, weld metal and weld joint has been carried out at 873 and 923 K at stress levels of 100-325 MPa with rupture lives in the range of 100-33,000 h. Weld strength reduction factors (WSRFs) based on the weld metal, and weld joint have been evaluated, and compared with the codes. WSRFs for the weld joint were higher than the RCC-MR values. Base metal showed the highest rupture life at all the test conditions whereas the weld metal generally showed the lowest rupture life. All the weld joint specimens failed in the weld metal

  18. Fracture toughness of austenitic stainless steel weld metal at 4 K

    International Nuclear Information System (INIS)

    Goodwin, G.M.

    1984-08-01

    Selection of the welding processess and weld filler metals for fabrication of a large toroidal superconducting magnet is described. Data available in the literature are collected and compared with data generated in this study for three welding processes, shielded metal arc (SMA), gas tungsten arc (GTA), and flux cored arc (FCA) welds had the highest fracture toughness as measured by K/sub Ic/ estimated from J/sub Ic/. The SMA and FCA welds had about the same toughness, below the GTA values but above the average from the literature. The fracture mode for all three processes was typified by ductile dimples. The fracture morphology of the FCA weld specimens was influenced by the solidification substructure, and small particles were found to be nucleation sites for void formation, especially for the GTA welds. All three welding processes were deemed adequate for the intended service and were used to fabricate the large magnet. A trunnion-type turning fixture eliminated the need for welding in the vertical and overhead positions. The GTA process was used for all root passes, and the horizontal welds were filled by the SMA process. Over 80% of the welds were done in the flat position with the FCA process, and its high deposition rate and ease of operation are credited with contributing greatly to the success of the effort

  19. Determination of Ductile Tearing Resistance Curve in Weld Joints

    International Nuclear Information System (INIS)

    Marie, S.; Gilles, P.; Ould, P.

    2010-01-01

    Steels present in the ductile domain a tearing resistance which increase with the crack propagation up to the failure. This ductile tearing resistance is in general characterised with curves giving the variation of a global parameter (opening displacement at the crack tip delta, integral J) versus the crack extension Delta a. These global approaches depend more or less on the specimen geometry and on the type of the imposed loading. Local approaches based on the description of the ductile tearing mechanisms provide reliable solution to the transferability problem (from the lab specimen to the component) but are complex and costly to use and are not codified. These problems get worse in the case of a weld joint where no standard is available for the measurement of their ductile tearing resistance. But the welded joints are often the weak point of the structure because of greater risk of defects, the heterogeneity of the microstructure of the weld, deformation along the interface between two materials with different yield stress (mismatch).... After briefly recalling the problems of transferability of the ductile tearing resistance curves obtained on lab specimen to the case of components, this article identifies the factors complicating the determination of the toughness in the welded joints and gives recommendations for the experimental determination of ductile tearing resistance curves of welded joints

  20. Influence of induction hardening parameters on the GS30Mn5 weld properties

    Directory of Open Access Journals (Sweden)

    V. Marušić

    2016-10-01

    Full Text Available This study examines parameters of post-weld heat treatment on the test specimens made of cast steel GS30Mn5. The welding is performed with shielded metal arc welding (SMAW process. The aim is to obtain the surface without illicit cracks, with hardness ranging from 320 up to 400 HB. After induction heating, the specimens are cooled alternately with air and water. Decreased speed of quenching results in avoiding the occurrence of illicit splashes, while the hardness is maintained within the prescribed limits.

  1. Performance of high molybdenum superaustenitic stainless steel welds in harsh chloride environments

    International Nuclear Information System (INIS)

    Stenvall, P.; Liljas, M.; Wallen, B.

    1996-01-01

    Superaustenitic steels are normally welded with nickel-based alloys as filler materials. To clarify the understanding of weld behavior in superaustenitic stainless steels this paper presents the development history of 6Mo and 7Mo steels, and results of laboratory tests and field tests on welds of UNS S31254 (6Mo) and UNS S32654 (7 Mo) in different types of chloride containing environments. The laboratory tests consisted of the well known ferric chloride test (ASTM G 48 Method A). Shielded metal arc welds, gas tungsten arc welds and submerged arc welds in both grades were tested. The critical pitting temperatures were determined and the locations of the attack were noted. Some specimens were sectioned at the position of the attack followed by studies using light optical microscopy. The critical pitting temperatures of the welds in S31254 and S32654 were at normal levels for both grades, i.e., 40--50 C for S31254 and 60--75 C for S32654. The locations of the attack differed depending on the welding process. In shielded metal arc welds the attack was mostly located in the weld metal. In gas tungsten arc welds the attack was predominantly located next to the fusion line. The field tests showed that the behavior of welds and parent metal of superaustenitic stainless steels, as well as of nickel-based alloys, is much dependent on the corrosive environment. In oxidizing chloride solutions, similar results to those of the ferric chloride test, are observed. However, crevice corrosion in the parent material is at a greater risk than pitting corrosion in the welds. In very oxidizing solutions of low chloride concentrations, welds made of nickel-based fillers may corrode faster than the stainless steel base metal due to transpassive uniform corrosion. The opposite situation exists when active uniform corrosion prevails, i.e., welds made of nickel-based fillers corrode less than the stainless steel parent material

  2. Dual wire welding torch and method

    Science.gov (United States)

    Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

    2009-04-28

    A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

  3. Electric arc welding gun

    Science.gov (United States)

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  4. Electron beam welding

    International Nuclear Information System (INIS)

    Schwartz, M.M.

    1974-01-01

    Electron-beam equipment is considered along with fixed and mobile electron-beam guns, questions of weld environment, medium and nonvacuum welding, weld-joint designs, tooling, the economics of electron-beam job shops, aspects of safety, quality assurance, and repair. The application of the process in the case of individual materials is discussed, giving attention to aluminum, beryllium, copper, niobium, magnesium, molybdenum, tantalum, titanium, metal alloys, superalloys, and various types of steel. Mechanical-property test results are examined along with the areas of application of electron-beam welding

  5. Robot welding process control

    Science.gov (United States)

    Romine, Peter L.

    1991-01-01

    This final report documents the development and installation of software and hardware for Robotic Welding Process Control. Primary emphasis is on serial communications between the CYRO 750 robotic welder, Heurikon minicomputer running Hunter & Ready VRTX, and an IBM PC/AT, for offline programming and control and closed-loop welding control. The requirements for completion of the implementation of the Rocketdyne weld tracking control are discussed. The procedure for downloading programs from the Intergraph, over the network, is discussed. Conclusions are made on the results of this task, and recommendations are made for efficient implementation of communications, weld process control development, and advanced process control procedures using the Heurikon.

  6. Use of servo controlled weld head for end closure welding

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, S.K.; Setty, D.S.; Rameswara Rao, A.; Hemantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2010-07-01

    In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

  7. Low Cycle Fatigue behavior of SMAW welded Alloy28 superaustenitic stainless steel at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kchaou, Y., E-mail: yacinekchaou@yahoo.fr [Institut Pprime, Département Physique et Mécanique des Matériaux, UPR 3346 CNRS ISAE-ENSMA Université de Poitiers, Téléport 2, 1, avenue Clément Ader, BP 40109, F – 86961 Futuroscope Chasseneuil Cedex (France); Laboratoire de Génie des Matériaux et Environnement (LGME), ENIS, BPW 1173, Sfax (Tunisia); Pelosin, V.; Hénaff, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, UPR 3346 CNRS ISAE-ENSMA Université de Poitiers, Téléport 2, 1, avenue Clément Ader, BP 40109, F – 86961 Futuroscope Chasseneuil Cedex (France); Haddar, N.; Elleuch, K. [Laboratoire de Génie des Matériaux et Environnement (LGME), ENIS, BPW 1173, Sfax (Tunisia)

    2016-01-10

    This paper focused on the study of Low Cycle Fatigue of welded joints of superaustenitic (Alloy28) stainless steels. Chemical composition and microstructure investigation of Base Metal (BM) and Weld Metal (WM) were identified. The results showed that both of composition is fully austenitic with a dendritic microstructure in the WM. Low cycle fatigue tests at different strain levels were performed on Base Metal (BM) and Welded Joint (WJ) specimens with a strain ratio R{sub ε}=−1. The results indicated that the fatigue life of welded joints is lower than the base metal. This is mainly due to the low ductility of the Welded Metal (WM) and the presence of welding defects. Simultaneously, Scanning Electron Microscope (SEM) observations of fractured specimens show that WJ have brittle behavior compared to BM with the presence of several welding defects especially in the crack initiation site. An estimation of the crack growth rate during LCF tests of BM and WJ was performed using distance between striations. The results showed that the crack initiation stage is shorter in the case of WJ compared to BM because of the presence of welding defects in WJ specimens.

  8. Fatigue Assessment of High Strength Steel Welded Joints Under Bending Loading

    International Nuclear Information System (INIS)

    Lee, Myeong-Woo; Kim, Yun-Jae; Park, Jun-Hyub

    2014-01-01

    In this study, a fatigue assessment method for vehicle suspension systems having welded geometries was established under a bending loading condition. For the fatigue life estimation of the actual product s welded joints made of different steels, bending fatigue tests were performed on welded specimens with a simplified shape for obtaining the moment-fatigue-life plot. Further, geometry modeling of the simplified welded specimens was conducted. Results of finite element analysis were used to obtain the stress-fatigue-life plot. The analysis results were also used to calculate the stress concentration factors for notch-factor-based fatigue life estimation. The test results were compared with results of the general notch-factor-based fatigue life estimation for improving fatigue assessment. As a result, it was concluded that both the welded fatigue tests and the notch-factor-based fatigue life estimation are necessary for accurate fatigue assessment

  9. Analysis of cracks in stainless steel TIG [tungsten inert gas] welds

    International Nuclear Information System (INIS)

    Nakagaki, M.; Marschall, C.; Brust, F.

    1986-12-01

    This report contains the results of a combined experimental and analytical study of ductile crack growth in tungsten inert gas (TIG) weldments of austenitic stainless steel specimens. The substantially greater yield strength of the weld metal relative to the base metal causes more plastic deformation in the base metal adjacent to the weld than in the weld metal. Accordingly, the analytical studies focused on the stress-strain interaction between the crack tip and the weld/base-metal interface. Experimental work involved tests using compact (tension) specimens of three different sizes and pipe bend experiments. The compact specimens were machined from a TIG weldment in Type 304 stainless steel plate. The pipe specimens were also TIG welded using the same welding procedures. Elastic-plastic finite element methods were used to model the experiments. In addition to the J-integral, different crack-tip integral parameters such as ΔT/sub p/* and J were evaluated. Also, engineering J-estimation methods were employed to predict the load-carrying capacity of the welded pipe with a circumferential through-wall crack under bending

  10. Corrosion behavior of welds in oxygen containing liquid lead

    Energy Technology Data Exchange (ETDEWEB)

    Heinzel, A.; Weisenburger, A.; Mueller, G. [Karlsruhe Institute of Technology (Germany). Inst. for Pulsed Power and Microwave Technology

    2012-11-01

    Liquid lead (Pb) and lead-bismuth eutectic (LBE) have been considered as coolant and/or spallation target in future accelerator driven systems (ADS). Therefore, in the recent years a lot of corrosion experiments on conventional steels were carried out in these heavy liquid metals. Beside these experiments, also tests on welded joints are required. Therefore ferritic/martensitic (F/M) steels (P91, P92) as well as an ODS steel were joint with TIG (Tungsten-Inert-Gas), EB (Electron Beam) and friction stir welding. After that, specimens were exposed to 10{sup -6} and 10{sup -8}wt% oxygen containing lead at 550 C for about 2000h. Weld regions having similar chemical composition and similar structure due to a heat treatment after the welding process show a corrosion behaviour under these conditions that is similar to that of the respective bulk material. (orig.)

  11. Fracture toughness of fabrication welds investigated by metallographic methods

    International Nuclear Information System (INIS)

    Canonico, D.A.; Crouse, R.S.

    1978-01-01

    The intermediate scale test vessels (ITV) were fabricated to provide test specimens that have sufficient wall thickness and simulate light water reactor pressure vessels. They were fabricated from grades of steel that are similar to those used for nuclear pressure vessels, having a wall thickness of 150mm and the same welded construction. They are, however, considerably smaller in height and diameter than actual vessels. To date, ten vessels have been fabricated and eight have been tested. In preparation for testing the eighth vessel (ITV-8), an extensive investigation was conducted of the toughness properties of the fabrication weld. It was thoroughly characterized and the fracture specimens used in this metallographic investigation were taken from that weld metal

  12. NASA Biological Specimen Repository

    Science.gov (United States)

    McMonigal, K. A.; Pietrzyk, R. A.; Sams, C. F.; Johnson, M. A.

    2010-01-01

    The NASA Biological Specimen Repository (NBSR) was established in 2006 to collect, process, preserve and distribute spaceflight-related biological specimens from long duration ISS astronauts. This repository provides unique opportunities to study longitudinal changes in human physiology spanning may missions. The NBSR collects blood and urine samples from all participating ISS crewmembers who have provided informed consent. These biological samples are collected once before flight, during flight scheduled on flight days 15, 30, 60, 120 and within 2 weeks of landing. Postflight sessions are conducted 3 and 30 days after landing. The number of in-flight sessions is dependent on the duration of the mission. Specimens are maintained under optimal storage conditions in a manner that will maximize their integrity and viability for future research The repository operates under the authority of the NASA/JSC Committee for the Protection of Human Subjects to support scientific discovery that contributes to our fundamental knowledge in the area of human physiological changes and adaptation to a microgravity environment. The NBSR will institute guidelines for the solicitation, review and sample distribution process through establishment of the NBSR Advisory Board. The Advisory Board will be composed of representatives of all participating space agencies to evaluate each request from investigators for use of the samples. This process will be consistent with ethical principles, protection of crewmember confidentiality, prevailing laws and regulations, intellectual property policies, and consent form language. Operations supporting the NBSR are scheduled to continue until the end of U.S. presence on the ISS. Sample distribution is proposed to begin with selections on investigations beginning in 2017. The availability of the NBSR will contribute to the body of knowledge about the diverse factors of spaceflight on human physiology.

  13. Mechanical properties of friction stir welded aluminum alloys 5083 and 5383

    Directory of Open Access Journals (Sweden)

    Jeom Kee Paik

    2009-09-01

    Full Text Available The use of high-strength aluminum alloys is increasing in shipbuilding industry, particularly for the design and construction of war ships, littoral surface craft and combat ships, and fast passenger ships. While various welding methods are used today to fabricate aluminum ship structures, namely gas metallic arc welding (GMAW, laser welding and friction stir welding (FSW, FSW technology has been recognized to have many advantages for the construction of aluminum structures, as it is a low-cost welding process. In the present study, mechanical properties of friction stir welded aluminum alloys are examined experimentally. Tensile testing is undertaken on dog-bone type test specimen for aluminum alloys 5083 and 5383. The test specimen includes friction stir welded material between identical alloys and also dissimilar alloys, as well as unwelded (base alloys. Mechanical properties of fusion welded aluminum alloys are also tested and compared with those of friction stir welded alloys. The insights developed from the present study are documented together with details of the test database. Part of the present study was obtained from the Ship Structure Committee project SR-1454 (Paik, 2009, jointly funded by its member agencies.

  14. Rotating specimen rack repair

    International Nuclear Information System (INIS)

    Miller, G.E.; Rogers, P.J.; Nabor, W.G.; Bair, H.

    1984-01-01

    In 1980, an operator at the UCI TRIGA Reactor noticed difficulties with the rotation of the specimen rack. Investigations showed that the drive bearing in the rack had failed and allowed the bearings to enter the rack. After some time of operation in static mode it was decided that installation of a bearing substitute - a graphite sleeve - would be undertaken. Procedures were written and approved for removal of the rack, fabrication and installation of the sleeve, and re-installation of the rack. This paper describes these procedures in some detail. Detailed drawings of the necessary parts may be obtained from the authors

  15. Method for thinning specimen

    Science.gov (United States)

    Follstaedt, David M.; Moran, Michael P.

    2005-03-15

    A method for thinning (such as in grinding and polishing) a material surface using an instrument means for moving an article with a discontinuous surface with an abrasive material dispersed between the material surface and the discontinuous surface where the discontinuous surface of the moving article provides an efficient means for maintaining contact of the abrasive with the material surface. When used to dimple specimens for microscopy analysis, a wheel with a surface that has been modified to produce a uniform or random discontinuous surface significantly improves the speed of the dimpling process without loss of quality of finish.

  16. A comparative study of the microstructure and mechanical properties of HTLA steel welds obtained by the tungsten arc welding and resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Ghazanfari, H., E-mail: ghazanfari@aut.ac.ir [AmirKabir University of Technology, Department of Mining and Metallurgy, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Naderi, M., E-mail: mnaderi@aut.ac.ir [AmirKabir University of Technology, Department of Mining and Metallurgy, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Iranmanesh, M., E-mail: imehdi@aut.ac.ir [AmirKabir University of Technology, Department of Maritime Engineering, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Seydi, M., E-mail: afsan_sy@yahoo.com [Zarin Joosh Aria Co., Tehran (Iran, Islamic Republic of); Poshteban, A., E-mail: ali_poshtiban@yahoo.com [Hamyar Sanat Eghbal Co., Tehran (Iran, Islamic Republic of)

    2012-02-01

    Highlights: Black-Right-Pointing-Pointer Hardness mapping is a novel method to identify different phases. Black-Right-Pointing-Pointer Surface hardness mapping, tabulates the hardness of a large area of weld. Black-Right-Pointing-Pointer Hardness maps can be used to depict the strength map through the specimen. Black-Right-Pointing-Pointer Hardness mapping is an easy way to identify the phase fractions within the specimen. - Abstract: Hardness tests are routinely employed as simple and efficient methods to investigate the microstructure and mechanical properties of steels. Each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data over a large area of weld zone would be a reasonable method to identify the present phases in steel. The microstructure distribution and mechanical properties variation through welded structures is inhomogeneous and not suitable for certain applications. So, studying the microstructure of weld zone has a significant importance. 4130 steel is classified in HTLA steels and it is widely used in marine industry due to its superior hardenability, good corrosion resistance and high strength. Gas tungsten arc and resistance spot welding are the most usable processes in joining of 4130 sheets. In this work a series of welds have been fabricated in 4130 steel tube by gas tungsten arc and resistance spot welding. The tube was subjected to quench-tempered heat treatment. Slices from the welds before and after heat treatment were polished and etched and the macrostructure and microstructure were observed. Hardness maps were then determined over the large area of weld zone, including the heat affected zone and base plate. Results show good relations between the various microstructures, strength and hardness values. It is also proved that this method is precise and applicable to estimate phase fraction of each phase in various regions of weld. In the current study some equations were proposed to

  17. A comparative study of the microstructure and mechanical properties of HTLA steel welds obtained by the tungsten arc welding and resistance spot welding

    International Nuclear Information System (INIS)

    Ghazanfari, H.; Naderi, M.; Iranmanesh, M.; Seydi, M.; Poshteban, A.

    2012-01-01

    Highlights: ► Hardness mapping is a novel method to identify different phases. ► Surface hardness mapping, tabulates the hardness of a large area of weld. ► Hardness maps can be used to depict the strength map through the specimen. ► Hardness mapping is an easy way to identify the phase fractions within the specimen. - Abstract: Hardness tests are routinely employed as simple and efficient methods to investigate the microstructure and mechanical properties of steels. Each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data over a large area of weld zone would be a reasonable method to identify the present phases in steel. The microstructure distribution and mechanical properties variation through welded structures is inhomogeneous and not suitable for certain applications. So, studying the microstructure of weld zone has a significant importance. 4130 steel is classified in HTLA steels and it is widely used in marine industry due to its superior hardenability, good corrosion resistance and high strength. Gas tungsten arc and resistance spot welding are the most usable processes in joining of 4130 sheets. In this work a series of welds have been fabricated in 4130 steel tube by gas tungsten arc and resistance spot welding. The tube was subjected to quench-tempered heat treatment. Slices from the welds before and after heat treatment were polished and etched and the macrostructure and microstructure were observed. Hardness maps were then determined over the large area of weld zone, including the heat affected zone and base plate. Results show good relations between the various microstructures, strength and hardness values. It is also proved that this method is precise and applicable to estimate phase fraction of each phase in various regions of weld. In the current study some equations were proposed to calculate the ultimate tensile stress and yield stress from the weld. The calculated data were compared

  18. Microstructure of bonding interface for resistance welding of Zr-based metallic glass sheets

    International Nuclear Information System (INIS)

    Kuroda, Toshio; Ikeuchi, Kenji; Shimada, Masahiro; Kobayashi, Akira; Kimura, Hisamichi; Inoue, Akihisa

    2009-01-01

    Resistance welding of Zr 55 Cu 30 Al 10 Ni 5 metallic glass sheets was investigated at 723 K in a supercooled liquid region. The welding time was changed from 5 s to 20 s at 723 K. The joint interface of the metallic glass was no defect and no crack. X-ray diffraction technique of the bonding interface of specimens was performed. The specimens showed halo patterns showing existence of only glassy phase, when the welding time was 5 s and 10 s. X-ray diffraction patterns of specimen bonded for 20 s showed crystalline peaks with halo patterns for the welding for 20 s. The crystalline phase at the bonding interface was small. Transmission electron micrograph at the bonding interface showed nanostructures of NiZr 2 and Al 5 Ni 3 Zr 2 . (author)

  19. Development of welding technique by remote control at the JMTR Hot Laboratory

    International Nuclear Information System (INIS)

    Shimizu, Michio; Iwamatu, Sigemi; Takada, Humiki

    2000-03-01

    Several kinds of welding techniques have been systematically developed using the remote controlled procedures in the JMTR Hot Laboratory. These are as follows, (1) re-instrumentation's of FP gas pressure gauge and thermocouple to an irradiated fuel rod for the centerline temperature measurement, (2) welding of the un-irradiated/irradiated specimen and machining process to produce tensile test specimens, (3) fabrication of Co-60 radiation source from materials for reactivity adjustment in JMTR core, (4) re-capsuling of irradiated materials in the different types of irradiation facilities. These research and development of circumferential and sealed welding for capsuling and welding of irradiated specimen for re-irradiation were implemented under the remote-controlled conditions in the Hot Cell. These techniques will be very indispensable for supporting the irradiation experiments to be conducted in the JMTR. (author)

  20. High Strain Rate Testing of Welded DOP-26 Iridium

    Energy Technology Data Exchange (ETDEWEB)

    Schneibel, J. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, R. G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carmichael, C. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fox, E. E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    The iridium alloy DOP-26 is used to produce Clad Vent Set cups that protect the radioactive fuel in radioisotope thermoelectric generators (RTGs) which provide electric power for spacecraft and rovers. In a previous study, the tensile properties of DOP-26 were measured over a wide range of strain rates and temperatures and reported in ORNL/TM-2007/81. While that study established the properties of the base material, the fabrication of the heat sources requires welding, and the mechanical properties of welded DOP-26 have not been extensively characterized in the past. Therefore, this study was undertaken to determine the mechanical properties of DOP-26 specimens containing a transverse weld in the center of their gage sections. Tensile tests were performed at room temperature, 750, 900, and 1090°C and engineering strain rates of 1×10-3 and 10 s-1. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1×10-4 Torr. The welded specimens had a significantly higher yield stress, by up to a factor of ~2, than the non-welded base material. The yield stress did not depend on the strain rate except at 1090°C, where it was slightly higher for the faster strain rate. The ultimate tensile stress, on the other hand, was significantly higher for the faster strain rate at temperatures of 750°C and above. At 750°C and above, the specimens deformed at 1×10-3 s-1 showed pronounced necking resulting sometimes in perfect chisel-edge fracture. The specimens deformed at 10 s-1 exhibited this fracture behavior only at the highest test temperature, 1090°C. Fracture occurred usually in the fusion zone of the weld and was, in most cases, primarily intergranular.

  1. Application of the simplified J-estimation scheme Aramis to mismatching welds in CCP

    International Nuclear Information System (INIS)

    Eripret, C.; Franco, C.; Gilles, P.

    1995-01-01

    The J-based criteria give reasonable predictions of the failure behaviour of ductile cracked metallic structures, even if the material characterization may be sensitive to the size of the specimens. However in cracked welds, this phenomenon due to stress triaxiality effects could be enhanced. Furthermore, the application of conventional methods of toughness measurement (ESIS or ASTM standard) have evidenced a strong influence of the portion of the weld metal in the specimen. Several authors have shown the inadequacy of the simplified J-estimation methods developed for homogeneous materials. These heterogeneity effects mainly related to the mismatch ratio (ratio of weld metal yield strength upon base metal yield strength) as well as to the geometrical parameter h/W-a (weld width upon ligament size). In order to make decisive progress in this field, the Atomic Energy Commission (CEA), the PWR manufacturer FRAMATOME, and the French utility (EDF) have launched a large research program on cracked piping welds behaviour. As part of this program, a new J-estimation scheme, so called ARAMIS, has been developed to account for the influence of both materials, i.e. base metal and weld metal, on the structural resistance of cracked welds. It has been shown that, when the mismatch is high, and when the ligament size is small compared to the weld width, a classical J-based method using the softer material properties is very conservative. On the opposite the ARAMIS method provides a good estimate of J, because it predicts pretty well the shift of the cracked weld limit load, due to the presence of the weld. the influence of geometrical parameters such as crack size, weld width, or specimen length is property accounted for. (authors). 23 refs., 8 figs., 1 tab., 1 appendix

  2. Measuring weld heat to evaluate weld integrity

    Energy Technology Data Exchange (ETDEWEB)

    Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

    2015-11-15

    Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

  3. Spatially resolved ultrasonic attenuation in resistance spot welds: implications for nondestructive testing.

    Science.gov (United States)

    Mozurkewich, George; Ghaffari, Bita; Potter, Timothy J

    2008-09-01

    Spatial variation of ultrasonic attenuation and velocity has been measured in plane parallel specimens extracted from resistance spot welds. In a strong weld, attenuation is larger in the nugget than in the parent material, and the region of increased attenuation is surrounded by a ring of decreased attenuation. In the center of a stick weld, attenuation is even larger than in a strong weld, and the low-attenuation ring is absent. These spatial variations are interpreted in terms of differences in grain size and martensite formation. Measured frequency dependences indicate the presence of an additional attenuation mechanism besides grain scattering. The observed attenuations do not vary as commonly presumed with weld quality, suggesting that the common practice of using ultrasonic attenuation to indicate weld quality is not a reliable methodology.

  4. Strain hardening and damage in 6xxx series aluminum alloy friction stir welds

    DEFF Research Database (Denmark)

    Simar, Aude; Nielsen, Kim Lau; de Meester, Bruno

    2010-01-01

    A friction stir weld in 6005A-T6 aluminum alloy has been prepared and analyzed by micro-hardness measurements, tensile testing and scanning electron microscopy (SEM). The locations of the various weld zones were determined by micro-hardness indentation measurements. The flow behavior of the various...... zones of the weld was extracted using micro-tensile specimens cut out parallel to the welding direction. The measured material properties and weld topology were then introduced in a fully coupled micro-mechanical finite element model, accounting for nucleation and growth of voids as well as void shape...... evolution. The model shows satisfactory preliminary results in predicting the tensile behaviour of the weld and the true strain at fracture....

  5. Effect of Thermal Aging and Test Temperatures on Fracture Toughness of SS 316(N) Welds

    Science.gov (United States)

    Dutt, B. Shashank; Babu, M. Nani; Shanthi, G.; Moitra, A.; Sasikala, G.

    2018-03-01

    The effect of thermal aging and test temperatures on fracture toughness (J 0.2) of SS 316(N) weld material has been studied based on J-R curve evaluations. The aging of the welds was carried out at temperatures 370, 475 and 550 °C and for durations varying from 1000 to 20,000 h. The fracture toughness (J-R curve) tests were carried out at 380 and 550 °C for specimens after all aging conditions, including as-weld condition. The initiation fracture toughness (J 0.2) of the SS 316(N) weld material has shown degradation after 20,000-h aging durations and is reflected in all the test temperatures and aging temperatures. The fracture toughness after different aging conditions and test temperatures, including as-weld condition, was higher than the minimum specified value for this class of welds.

  6. Microstructure and mechanical properties of friction stir welded SAF 2507 super duplex stainless steel

    International Nuclear Information System (INIS)

    Sato, Y.S.; Nelson, T.W.; Sterling, C.J.; Steel, R.J.; Pettersson, C.-O.

    2005-01-01

    The microstructure and mechanical properties of friction stir (FS) welded SAF 2507 super duplex stainless steel were examined. High-quality, full-penetration welds were successfully produced in the super duplex stainless steel by friction stir welding (FSW) using polycrystalline cubic boron nitride (PCBN) tool. The base material had a microstructure consisting of the ferrite matrix with austenite islands, but FSW refined grains of the ferrite and austenite phases in the stir zone through dynamic recrystallisation. Ferrite content was held between 50 and 60% throughout the weld. The smaller grain sizes of the ferrite and austenite phases caused increase in hardness and strength within the stir zone. Welded transverse tensile specimen failed near the border between the stir zone and TMAZ at the retreating side as the weld had roughly the same strengths as the base material

  7. TIG welding method and TIG welding device

    International Nuclear Information System (INIS)

    Yoneda, Eishi

    1998-01-01

    The present invention provides a method of TIG welding for members having different heat capacities including a cladding tube and an end plug of a fuel rod to be used, for example, in a reactor, and a device therefor. Namely, in the TIG welding method, the flow rate of a sealed gas to the side of a member having smaller heat capacity is made greater than that on the side of the member having greater heat capacity bordered on the top end of a welding electrode. Since the sealed gas is jetted being localized relative to the welding electrode, arc is restricted in a region of the member having smaller heat capacity and is increased at a region having a larger heat capacity. As a result, the arc is localized, so that the heat input amount to the region having a large heat capacity is increased, and then a plurality of members at the abutting portion are melted uniformly thereby capable of obtaining a uniform molten pool. A bead is formed at the abutting portion thereby capable of obtaining a welded portion with less unevenness and having large strength. (I.S.)

  8. Explosion metal welding

    International Nuclear Information System (INIS)

    Popoff, A.A.

    1976-01-01

    Process parameters pertaining to welding similar and dissimilar metals using explosives are reviewed. The discussion centers on the interrelationship of physical parameters which play a part in achieving desirable metallurgical results. Present activities in explosion metal welding at LASL are presented and shown how they related to the interests of the ERDA community

  9. Electron beam welding

    International Nuclear Information System (INIS)

    Gabbay, M.

    1972-01-01

    The bead characteristics and the possible mechanisms of the electron beam penetration are presented. The different welding techniques are exposed and the main parts of an electron beam welding equipment are described. Some applications to nuclear, spatial and other industries are cited [fr

  10. Welding problems in nuclear power engineering

    International Nuclear Information System (INIS)

    Zubchenko, A.S.

    1986-01-01

    The problems of welding industry in nuclear power plant engineering, mainly related to the improvement of molten bath protection, are considered. Development of new materials for welding electrodes, for cladding and welding fluxes, is pointed out. Production of the following equipment is brought to a commercial level: welding heads and welding machines for branch pipe welding, anticorrosion cladding, zonal thermal treatment, electron beam welding facilities for the welding and maintenance of turbineblades, equipment for nondestructive testing of welded joints

  11. Fundamental Study of Electron Beam Welding of AA6061-T6 Aluminum Alloy for Nuclear Fuel Plate Assembly (II)

    International Nuclear Information System (INIS)

    Kim, Soosung; Lee, Haein; Lee, Donbae; Park, Jongman; Lee, Yoonsang

    2013-01-01

    Certain characteristics, such as solidification cracking, porosity, HAZ (Heat-affected Zone) degradation must be considered during welding. Because of high energy density and low heat input, especially LBW and EBW processes posses the advantage of minimizing the fusing zone and HAZ and producing deeper penetration than arc welding processes. In present study, to apply for the nuclear fuel plate fabrication and assembly, a fundamental EBW experiment using AA6061-T6 aluminum alloy specimens was conducted. Furthermore, to establish the welding process, and satisfy the requirements of the weld quality, EBW apparatus using a electron welding gun and vacuum chamber was developed, and preliminary investigations for optimizing the welding parameters of the specimens using AA6061-T6 aluminum plates were also performed. In this experiment, a feasibility test was carried out by tensile tester, bead-on-plate welding and metallographic examination to comply with the aluminum welding procedure. The EB weld quality of AA6061-T6 aluminum alloy for the fuel plate assembly has been also studied by the mechanical testing and microstructure examinations. This study was carried out to determine the suitable welding process and to investigate tensile strength of AA6061-T6 aluminum alloy. In the present experiment, satisfactory EBW of the square butt weld specimens was developed. In comparison with the rolling directions of test specimens, the tensile strengths were no difference between the longitudinal and transverse welds. Based on this fundamental study, fabrication and assembly of the nuclear fuel plates will be provided for the future Kijang research reactor project

  12. Method for welding beryllium

    Science.gov (United States)

    Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

    1997-04-01

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

  13. Method for welding beryllium

    International Nuclear Information System (INIS)

    Dixon, R.D.; Smith, F.M.; O'Leary, R.F.

    1997-01-01

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs

  14. Transition welds in welding of two-ply steels

    International Nuclear Information System (INIS)

    Fartushnyj, V.G.; Evsyukov, Yu.G.

    1977-01-01

    Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

  15. A Relationship of the Torque Strength between Endplates and Endcaps due to the Welding Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae Seo; Kim, Soo Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and an endcap, this welding part is connected with the safety of nuclear fuel rods. Endcap-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and an endcap is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and an endcap. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a fuel bundle welder to measure and analyze the torque strength of an endplate-endcap welding. The torque strength between endplates and endcaps was measured and analyzed with the welding current and the welding time. The torque strength between endplates and endcaps was, on the whole, within 6.9-12.7 N{center_dot}m in the range of fabrication specification of the fuel bundles. The weldability of between an endplate and an endcap was investigated by a metallographic examination.

  16. Grinding Parts For Automatic Welding

    Science.gov (United States)

    Burley, Richard K.; Hoult, William S.

    1989-01-01

    Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

  17. Investigation of endurance limit- and low-cycle fatigue strength of St E 47 and STE 70 in the welded and unwelded state

    International Nuclear Information System (INIS)

    Jaenicke, B.; Helms, R.; Florian, W.; Lipp, H.J.; Seidl, W.; Kaiser, B.

    1979-01-01

    To clarify clear the effect of the welding conditions and the heat treatment, alternating load tests were carried out in the endurance limit- and low-cycle-fatigue strength range on specimens of St E 47 and St E 70. Grounded basic material flat specimens cleared from their rolling skins and welded flat specimens with a butt weld of special quality were used. The welds were produced by the metal arc manual welding method with bar electrodes (low heat introduction) and with the submerged-arc welding method (high heat introduction). Part of the specimens were tempered free from stress after welding. The tests were carried out force-controlled at tension-repeated loading (S=0) and strain controlled at tension-compression alternating loading (S approx. -1). In the range of N = 5 x 10 4 ...1,5 x 10 6 cycles a small effect of the welding (special quality) for St E 47 with subsequence tempering on the endurance limit was proofed, which in comparison with the unwelded basic material (grounded surface) was characterized by broad range at nearly the same endurance limit. For St E 70, a clear decrease of the endurance limit of welded, tempered specimens (special quality) was found as compared with the basic material (grounded surface). (orig./RW) 891 RW/orig.- 892 RKD [de

  18. Prediction of Weld Residual Stress of Narrow Gap Welds

    International Nuclear Information System (INIS)

    Yang, Jun Seog; Huh, Nam Su

    2010-01-01

    The conventional welding technique such as shield metal arc welding has been mostly applied to the piping system of the nuclear power plants. It is well known that this welding technique causes the overheating and welding defects due to the large groove angle of weld. On the other hand, the narrow gap welding(NGW) technique has many merits, for instance, the reduction of welding time, the shrinkage of weld and the small deformation of the weld due to the small groove angle and welding bead width comparing with the conventional welds. These characteristics of NGW affect the deformation behavior and the distribution of welding residual stress of NGW, thus it is believed that the residual stress results obtained from conventional welding procedure may not be applied to structural integrity evaluation of NGW. In this paper, the welding residual stress of NGW was predicted using the nonlinear finite element analysis to simulate the thermal and mechanical effects of the NGW. The present results can be used as the important information to perform the flaw evaluation and to improve the weld procedure of NGW

  19. Capabilities of infrared weld monitor

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, P.G.; Keske, J.S.; Leong, K.H.; Kornecki, G.

    1997-11-01

    A non-obtrusive pre-aligned, solid-state device has been developed to monitor the primary infrared emissions during laser welding. The weld monitor output is a 100-1000 mV signal that depends on the beam power and weld characteristics. The DC level of this signal is related to weld penetration, while AC portions of the output can be correlated with surface irregularities and part misalignment or contamination. Changes in DC behavior are also noted for both full and deep penetration welds. Full penetration welds are signified by an abrupt reduction in the weld monitor output. Bead on plate welds were made on steel, aluminum, and magnesium with both a CW CO{sub 2} laser and a pulsed Nd:YAG laser to explore the relationships between the weld characteristics and the weld monitor output.

  20. Improvements in welding parameters for a new design of zircaloy-4 tube-end plug joints

    International Nuclear Information System (INIS)

    Martinez, R.L.; Fernandez, L.; Corso, H.L.; Ausas, J; Santisteban, J.R.

    2010-01-01

    This work presents the experimental results for the characterization of welds using a new design for zircaloy-4 tube-end plug joints, applicable to the production of fuel elements for the Atucha I Nuclear Plant. Test specimens were prepared following the new joint design and were welded using orbital welding equipment. Hydrogen content was measured in the different welding areas, and corrosion tests, and mechanical and microstructural descriptions were carried out, obtaining values that meet the current production standards. We reported previously that test samples welded in equipment with a smaller camera showed some relatively high hydrogen levels, together with alterations in the welded zone in the corrosion tests. Given these results, new tests were undertaken to optimize the welding parameters, being very careful with the purity of the welding atmosphere and in the handling of the samples. The intensity of the welding current was increased slightly to obtain better penetration of the material, without significantly increasing the heat input. The traction resistance values improved, reducing the hydrogen content to well below the maximum allowed by the standards (25 ppm) in all the welding zones and obtaining satisfactory results in the corrosion tests

  1. Micro–macro-characterisation and modelling of mechanical properties of gas metal arc welded (GMAW) DP600 steel

    Energy Technology Data Exchange (ETDEWEB)

    Ramazani, A., E-mail: ali.ramazani@iehk.rwth-aachen.de [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Mukherjee, K. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Abdurakhmanov, A. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Prahl, U. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Schleser, M.; Reisgen, U. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Bleck, W. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany)

    2014-01-01

    Dual-phase (DP) steels show combined high strength and adequate formability. However, during welding, their microstructural feature of dispersion of hard martensite islands in the soft ferrite matrix is lost and the properties deteriorate. The current research aims to study the mechanical properties of the welded joint, taking into account the effect of features of all regions, such as microstructure, chemical composition and the area fraction, on the macroscopic mechanical properties of the welded joint. Hot rolled DP 600 steel was gas metal arc welded (GMAW) and tensile specimens were made with a welded joint. In the heat-affected zone (HAZ), the microstructure varied from bainite to coarse grained ferrite and tempered martensite. Chemical composition of every quantified region in the welded specimen was also identified using electron probe microanalysis (EPMA). Macromechanical FE modelling was employed to simulate the mechanical properties of the welded tensile specimen. 2D representative volume elements (RVE) for different parts of the welded region were constructed from real microstructure. 2D simulated flow curves were corrected to 3Ds using a developed correlation factor. Finally, the tensile test of welded material with inhomogeneous morphology was simulated and good agreement between experimental and predicted flow curve was achieved.

  2. Micro–macro-characterisation and modelling of mechanical properties of gas metal arc welded (GMAW) DP600 steel

    International Nuclear Information System (INIS)

    Ramazani, A.; Mukherjee, K.; Abdurakhmanov, A.; Prahl, U.; Schleser, M.; Reisgen, U.; Bleck, W.

    2014-01-01

    Dual-phase (DP) steels show combined high strength and adequate formability. However, during welding, their microstructural feature of dispersion of hard martensite islands in the soft ferrite matrix is lost and the properties deteriorate. The current research aims to study the mechanical properties of the welded joint, taking into account the effect of features of all regions, such as microstructure, chemical composition and the area fraction, on the macroscopic mechanical properties of the welded joint. Hot rolled DP 600 steel was gas metal arc welded (GMAW) and tensile specimens were made with a welded joint. In the heat-affected zone (HAZ), the microstructure varied from bainite to coarse grained ferrite and tempered martensite. Chemical composition of every quantified region in the welded specimen was also identified using electron probe microanalysis (EPMA). Macromechanical FE modelling was employed to simulate the mechanical properties of the welded tensile specimen. 2D representative volume elements (RVE) for different parts of the welded region were constructed from real microstructure. 2D simulated flow curves were corrected to 3Ds using a developed correlation factor. Finally, the tensile test of welded material with inhomogeneous morphology was simulated and good agreement between experimental and predicted flow curve was achieved

  3. The lack of penetration effect on fatigue crack propagation resistance of atmospheric corrosion resistant steel welded joints

    International Nuclear Information System (INIS)

    Martins, Geraldo de Paula; Cimini Junior, Carlos Alberto; Godefroid, Leonardo Barbosa

    2005-01-01

    The welding process introduces defects on the welded joints, as lack of fusion and penetration, porosity, between others. These defects can compromise the structures or components, relative to the crack propagation. This engagement can be studied by fatigue crack propagation tests. The efficiency of the structure, when submitted to a cyclic loading can be evaluated by these tests. The aim of this work is to study the behavior of welded joints containing defects as lack of penetration at the root or between welding passes relative to crack propagation resistance properties, and to compare these properties with the properties of the welded joints without defects. This study was accomplished from fatigue crack propagation test results, in specimens containing lack of penetration between welding passes. With the obtained results, the Paris equation coefficients and exponents that relate the crack propagation rate with the stress intensity cyclic factor for welded joints with and without defects were obtained. (author)

  4. The effect of plasma arc process parameters on the properties of dissimilar AISI 1040/AISI 304 steel plate welds

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Musa; Kirik, Ihsan; Orhan, Nuri [Firat Univ., Elazig (Turkey); Celik, Ferkan [Science Industry and Technology Ministry of Turkey (Turkey)

    2012-11-01

    In this study, 10 mm thick AISI 1040 and AISI 304 steel plates were welded in the butt position without pretreatment by plasma transferred arc (PTA) welding technique. Therefore, mechanical behaviour, microstructure, penetration depth and length were investigated. After welding, microstructural changes in the interface regions of the welded specimens were examined by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Micro-hardness as well as V-notch Charpy tests were performed to determine the mechanical properties of the welds. The influence of the welding parameters on the dimension and shape of the joints has been found out. From the results, it was derived that with the parameters used, a partly keyhole weld bead formed with a penetration depth of 10 mm and a width of 11 mm in butt position. (orig.)

  5. Mitigation of inside surface residual stress of type 304 stainless steel pipe welds by inside water cooling method

    International Nuclear Information System (INIS)

    Sasaki, R.

    1980-01-01

    The weld residual stress distributions, macro- and microstructures of heat affected zone and IGSCC susceptibility of Type 304 stainless steel pipe welds by natural and inside water cooling methods have been investigated. The residual stresses of pipe welds by the natural cooling method are high tensile on both the inside and the outside surface. While the residual stresses on the inside surface of pipe welds by the inside water cooling method are compressive in both axial and circumferential directions for each pipe size from 2 to 24 inch diameter. The sensitized zones of welds by the inside water cooling method are closer to the fusion line, much narrower and milder than those by the natural cooling method. According to the constant extension rate test results for specimens taken from the inside surface of pipe welds, the inside water cooled welds are more resistant to IGSCC than naturally cooled ones

  6. Microstructure, local and global mechanical properties of friction stir welds in aluminium alloy 6005A-T6

    International Nuclear Information System (INIS)

    Simar, A.; Brechet, Y.; Meester, B. de; Denquin, A.; Pardoen, T.

    2008-01-01

    The effect of the welding speed on the microstructure, local and overall mechanical properties of friction stir welded joints has been investigated in the aluminium alloy 6005A-T6. The fine hardening precipitation within the heat-affected zone has been characterized by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Post-welding heat treatments have been applied to obtain indications on the level of solid solution supersaturation in the as welded state. The local mechanical behaviour was determined using thin specimens extracted from various regions of the weld. The overall properties were measured on samples cut perpendicular to the weld. Specific attention was devoted to the relationship between the local microstructure and local hardening properties in the weakest region, which govern the overall strength and ductility of the welds

  7. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    Energy Technology Data Exchange (ETDEWEB)

    Das, C.R., E-mail: chitta@igcar.gov.in [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Albert, S.K. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Sam, Shiju [Institute for Plasma Research, Gandhinagar (India); Mastanaiah, P. [Defense Research and Development Laboratory, Hyderabad (India); Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T. [Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Murthy, C.V.S. [Defense Research and Development Laboratory, Hyderabad (India); Kumar, E. Rajendra [Institute for Plasma Research, Gandhinagar (India)

    2014-11-15

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition.

  8. Study on Microstructure and Mechanical Properties of 304 Stainless Steel Joints by Tig-Mig Hybrid Welding

    Science.gov (United States)

    Ogundimu, Emmanuel O.; Akinlabi, Esther T.; Erinosho, Mutiu F.

    Stainless steel is a family of Fe-based alloys having excellent resistance to corrosion and as such has been used imperatively for kitchen utensils, transportation, building constructions and much more. This paper presents the work conducted on the material characterizations of a tungsten inert gas (TIG)-metal inert gas (MIG) hybrid welded joint of type 304 austenitic stainless steel. The welding processes were conducted in three phases. The phases of welding employed are MIG welding using a current of 170A, TIG welding using a current of 190A, and a hybrid TIG-MIG welding with currents of 190/170A, respectively. The MIG, TIG, and hybrid TIG-MIG weldments were characterized with incomplete penetration, full penetration and excess penetration of weld. Intergranular austenite was created toward transition and heat affected zones. The thickness of the delta ferrite (δ-Fe) formed in the microstructures of the TIG weld is more than the thickness emerged in the microstructures of MIG and hybrid TIG-MIG welds. A TIG-MIG hybrid weld of specimen welded at the currents of 190/170A has the highest ultimate tensile strength value and percentage elongation of 397.72MPa and 35.7%. The TIG-MIG hybrid welding can be recommended for high-tech industrial applications such as nuclear, aircraft, food processing, and automobile industry.

  9. Mechanical properties of 9Cr–1W reduced activation ferritic martensitic steel weldment prepared by electron beam welding process

    International Nuclear Information System (INIS)

    Das, C.R.; Albert, S.K.; Sam, Shiju; Mastanaiah, P.; Chaitanya, G.M.S.K.; Bhaduri, A.K.; Jayakumar, T.; Murthy, C.V.S.; Kumar, E. Rajendra

    2014-01-01

    Highlights: • Width of HAZ is smaller in the 9Cr–1W RAFM weldment prepared by EB process compared to that reported for TIG weldments in literature. • Weld joint is stronger than that of the base metal. • Toughness of weld metal prepared by EB welding process is comparable to that (in PWHT condition) prepared by TIG process. • DBTT of as-welded 9Cr–1W RAFM weldment prepared by EB process is comparable to that reported for TIG weld metal in PWHT condition. - Abstract: Microstructure and mechanical properties of the weldments prepared from 9Cr–1W reduced activation ferritic martensitic (RAFM) steel using electron beam welding (EBW) process were studied. Microstructure consists of tempered lath martensite where precipitates decorating the boundaries in post weld heat treated (PWHT) condition. Lath and precipitate sizes were found to be finer in the weld metal than in base metal. Accordingly, hardness of the weld metal was found to be higher than the base metal. Tensile strength of the cross weldment specimen was 684 MPa, which was comparable with the base metal tensile strength of 670 MPa. On the other hand, DBTT of 9Cr–1W weld metal in as-welded condition is similar to that reported for TIG weld metal in PWHT condition

  10. Multipurpose ANSYS FE procedure for welding processes simulation

    Energy Technology Data Exchange (ETDEWEB)

    Capriccioli, Andrea [ENEA CR Frascati, Via Enrico Fermi 45, 00044 Frascati (Italy); Frosi, Paolo [ENEA CR Frascati, Via Enrico Fermi 45, 00044 Frascati (Italy)], E-mail: frosi@frascati.enea.it

    2009-06-15

    ANSYS FE procedures and 3D models for thermal and mechanical simulation of both Laser and TIG welding processes are presented. The special features are the applicability to a non uniform gap and the use of a fast iterative procedure that assures the constancy of the fixed maximum temperature along the single pass and between each pass and the following, apart from their shapes and sizes. All the thermal and mechanical material properties of both INCONEL 625 and AISI 316 are described till to liquid phase; convection and radiation effects are considered. The 3D ANSYS models use both brick and non linear contact elements and elastic and elastic-plastic materials. Two full simulation are presented: a laser welding test (taken from ENEA) and a TIG welding one (source W7-X) with the root seam plus 14 passes; thermal and mechanical results are reported in the two cases and for the latter an extensive sensitivity analysis, changing mesh size of the filling material, welding speed and material properties, is explained with results and comparisons. This large sensitivity analysis has been executed for TIG welding because in this case (multi-pass welding) the reduction of CPU time is a strong requirement; but some conclusions are helpful for laser welding too. The mechanical calculation results very sensitive to the mesh shape: this fact implies very fine and regular meshes. The specimens are first restrained and then welded with the foreseen welding procedure; after that it is released and the final linear and angular shrinkages are calculated. The ANSYS birth and death procedure is used and the CPU time was strongly reduced.

  11. Multipurpose ANSYS FE procedure for welding processes simulation

    International Nuclear Information System (INIS)

    Capriccioli, Andrea; Frosi, Paolo

    2009-01-01

    ANSYS FE procedures and 3D models for thermal and mechanical simulation of both Laser and TIG welding processes are presented. The special features are the applicability to a non uniform gap and the use of a fast iterative procedure that assures the constancy of the fixed maximum temperature along the single pass and between each pass and the following, apart from their shapes and sizes. All the thermal and mechanical material properties of both INCONEL 625 and AISI 316 are described till to liquid phase; convection and radiation effects are considered. The 3D ANSYS models use both brick and non linear contact elements and elastic and elastic-plastic materials. Two full simulation are presented: a laser welding test (taken from ENEA) and a TIG welding one (source W7-X) with the root seam plus 14 passes; thermal and mechanical results are reported in the two cases and for the latter an extensive sensitivity analysis, changing mesh size of the filling material, welding speed and material properties, is explained with results and comparisons. This large sensitivity analysis has been executed for TIG welding because in this case (multi-pass welding) the reduction of CPU time is a strong requirement; but some conclusions are helpful for laser welding too. The mechanical calculation results very sensitive to the mesh shape: this fact implies very fine and regular meshes. The specimens are first restrained and then welded with the foreseen welding procedure; after that it is released and the final linear and angular shrinkages are calculated. The ANSYS birth and death procedure is used and the CPU time was strongly reduced.

  12. Preliminary assessment of the fracture behavior of weld material in full-thickness clad beams

    International Nuclear Information System (INIS)

    Keeney, J.A.; Bass, B.R.; McAfee, W.J.; Iskander, S.K.

    1994-10-01

    This report describes a testing program that utilizes full-thickness clad beam specimens to quantify fracture toughness for shallow cracks in material for which metallurgical conditions are prototypic of those found in reactor pressure vessels (RPVs). The beam specimens are fabricated from a section of an RPV wall (removed from a canceled nuclear plant) that includes weld, plate, and clad material. Metallurgical factors potentially influencing fracture toughness for shallow cracks in the beam specimens include material gradients due to welding and cladding applications, as well as material inhomogeneities in welded regions due to reheating in multiple weld passes. A summary of the testing program includes a description of the specimen geometry, material properties, the testing procedure, and the experimental results form three specimens. The yield strength of the weld material was determined to be 36% higher than the yield strength of the base material. An irradiation-induced increase in yield strength of the weld material could result in a yield stress that exceeds the upper limit where code curves are valid. The high yield strength for prototypic weld material may have implications for RPV structural integrity assessments. Analyses of the test data are discussed, including comparisons of measured displacements with finite-element analysis results, applications of toughness estimation techniques, and interpretations of constraint conditions implied by stress-based constraint methodologies. Metallurgical conditions in the region of the cladding heat-affected zone are proposed as a possible explanation for the lower-bound fracture toughness measured with one of the shallow-crack clad beam specimens. Fracture toughness data from the three clad beam specimens are compared with other shallow- and deep-crack uniaxial beam and cruciform data generated previously from A 533 Grade B plate material

  13. Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

    International Nuclear Information System (INIS)

    Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

    2015-01-01

    In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

  14. Welding method, and welding device for use therein, and method of analysis for evaluating welds

    NARCIS (Netherlands)

    Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

    1995-01-01

    Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

  15. Effect of a shear modified Gurson model on damage development in a FSW tensile specimen

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Tvergaard, Viggo

    2009-01-01

    For a friction stir welded aluminum plate the resistance to ductile failure is studied by analyzing tensile test specimens cut out across the weldline. As the stress triaxiality is rather low in these tests, the Gurson material model is not expected to give a very accurate description of the void......, such that the damage parameter does not really represent the void volume fraction. Various amounts of the additional damage evolution are compared with predictions of the original Gurson model. The analyses are carried out for different yield stress profiles transverse to the weld and for different specimen widths....... It is found that the modification does provide additional damage development in the friction stir weld, which may help to fit experimental data. But the suggested modification depends strongly on the overall stress state, and may have a too strong effect in some cases where the stress triaxiality is rather...

  16. The effect of specimen thickness on the experimental and finite ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    as a fracture parameter and the J-CTOD relation for the determination of critical ... fracture behaviour of EDD (0·06%C) steel sheets with CT specimens and using ... On the other hand, in the predominantly plane stress region, if the toughness value ..... (iii) Hardness measurement – The plastic zone size and shape is also ...

  17. Weld analysis and control system

    Science.gov (United States)

    Kennedy, Larry Z. (Inventor); Rodgers, Michael H. (Inventor); Powell, Bradley W. (Inventor); Burroughs, Ivan A. (Inventor); Goode, K. Wayne (Inventor)

    1994-01-01

    The invention is a Weld Analysis and Control System developed for active weld system control through real time weld data acquisition. Closed-loop control is based on analysis of weld system parameters and weld geometry. The system is adapted for use with automated welding apparatus having a weld controller which is capable of active electronic control of all aspects of a welding operation. Enhanced graphics and data displays are provided for post-weld analysis. The system provides parameter acquisition, including seam location which is acquired for active torch cross-seam positioning. Torch stand-off is also monitored for control. Weld bead and parent surface geometrical parameters are acquired as an indication of weld quality. These parameters include mismatch, peaking, undercut, underfill, crown height, weld width, puddle diameter, and other measurable information about the weld puddle regions, such as puddle symmetry, etc. These parameters provide a basis for active control as well as post-weld quality analysis and verification. Weld system parameters, such as voltage, current and wire feed rate, are also monitored and archived for correlation with quality parameters.

  18. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2003-01-01

    Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

  19. Creep-fatigue propagation of semi-elliptical crack at 650 deg. C in 316L(N) stainless steel plates with or without welded joints; Propagation de fissures semi-elliptiques en fatigue-fluage a 650 deg. C dans des plaques d'acier 316L(N) avec ou sans joints soudes

    Energy Technology Data Exchange (ETDEWEB)

    Curtit, F

    2000-07-01

    This study realised in LISN Laboratory of CEA Saclay, deals with the creep fatigue propagation of semi elliptical crack at the temperature of 650 deg C in 316L(N) stainless steel plates with or without welded joints. A vast majority of the studies on creep fatigue propagation models are based on specimen (CT) especially designed for crack propagation study. The PLAQFLU program performed in LISN laboratory deals with the application and adaptation of these models to complex crack shape, which are more representative of the cracks observed in industrial components. In this scope, we use propagation tests realised at the temperature of 650 deg C with wide plates containing semi elliptical defects. For some of them, the initial defect is machined in the middle of a welded joint, which constitute a privileged site for the crack initiation. The approach used in this study is based on global parameters of fracture mechanics. At first, tests on CT specimen are used in order to determine the propagation laws correlating the crack growth rate to the global parameters K or C{sup *}. These laws are then supposed to be intrinsic to our materials and are used to analysed the semi elliptical crack propagation. The analysis of the comportment of the crack during the hold time demonstrates the possibility to establish a correlation between the crack propagation both in the deepest and the surface point and the local value of C{sup *}. These correlations are coherent in the different points of the crack front for the different applied hold times, and they present a reasonably good agreement with the creep propagation law identified on CT specimen. The simulation of test performed on based metal specimen with a model of summation of both creep and pure fatigue crack growth gives acceptable results when the calculus of the simplified expression of C{sup *}{sub s} considers a continuous evolution of creep deformations rate during the all test. (author)

  20. Normal CT anatomy of the spine

    International Nuclear Information System (INIS)

    Quiroga, O.; Matozzi, F.; Beranger, M.; Nazarian, S.; Salamon, G.; Gambarelli, J.

    1982-01-01

    To analyse the anatomo-radiological correlation of the spine and spinal cord, 22 formalized, frozen anatomical specimens corresponding to different regions of the spinal column (8 cervical, 5 dorsal, and 9 lumbar) were studied by CT scans on axial, sagittal and coronal planes and by contact radiography after they were cut into anatomical slices in order to clarify the normal CT anatomy of the spinal column. The results obtained from CT patient scans, performed exclusively on the axial plane, were compared with those obtained from the anatomical specimens (both CT and contrast radiography). High resolution CT programs were used, enabling us to obtain better individualization of the normal structures contained in the spinal column. Direct sagittal and coronal sections were performed on the specimens in order to get further anatomo-radiological information. Enhanced CT studies of the specimens were also available because of the air already present in the subarachnoid spaces. Excellent visualization was obtained of bone structures, soft tissue and the spinal cord. High CT resolution of the spine appeares to be an excellent neuroradiological procedure to study the spine and spinal cord. A metrizamide CT scan is, however, necessary when a normal unenhanced CT scan is insufficient for diagnosis and when the spinal cord is not clearly visible, as often happens at the cervical level. Clinical findings are certainly very useful to ascertain the exact CT level and to limit the radiation exposure. (orig.)

  1. Effect of post-weld heat treatment and electrolytic plasma processing on tungsten inert gas welded AISI 4140 alloy steel

    International Nuclear Information System (INIS)

    Dewan, Mohammad W.; Liang, Jiandong; Wahab, M.A.; Okeil, Ayman M.

    2014-01-01

    Highlights: • The effects of PWHT and EPP were explored on TIG welded AISI4140 alloy steel. • All welded samples were checked with PAUT and ensured defect-free before testing. • Residual stresses, hardness, and tensile properties were measured experimentally. • PWHT resulted higher ductility but lower tensile strength for grain refinement. • EPP-treated samples showed higher tensile strength but lower ductility. - Abstract: Post-weld heat treatment (PWHT) is commonly adopted on welded joints and structures to relieve post-weld residual stresses; and restore the mechanical properties and structural integrity. An electrolytic plasma process (EPP) has been developed to improve corrosion behavior and wear resistance of structural materials; and can be employed in other applications and surface modifications aspects. In this study the effects of PWHT and EPP on the residual stresses, micro-hardness, microstructures, and uniaxial tensile properties are explored on tungsten inert gas (TIG) welded AISI-4140 alloys steel with SAE-4130 chromium–molybdenum alloy welding filler rod. For rational comparison all of the welded samples are checked with nondestructive Phased Array Ultrasonic Testing (PAUT) and to ensure defect-free samples before testing. Residual stresses are assessed with ultrasonic testing at different distances from weld center line. PWHT resulted in relief of tensile residual stress due to grain refinement. As a consequence higher ductility but lower strength existed in PWHT samples. In comparison, EPP-treated samples revealed lower residual stresses, but no significant variation on the grain refinement. Consequently, EPP-treated specimens exhibited higher tensile strength but lower ductility and toughness for the martensitic formation due to the rapid heating and quenching effects. EPP was also applied on PWHT samples, but which did not reveal any substantial effect on the tensile properties after PWHT at 650 °C. Finally the microstructures and

  2. Effect of Low-Temperature Sensitization on the Corrosion Behavior of AISI Type 304L SS Weld Metal in Simulated Groundwater

    Science.gov (United States)

    Suresh, Girija; Nandakumar, T.; Viswanath, A.

    2018-05-01

    The manuscript presents the investigations carried out on the effect of low-temperature sensitization (LTS) of 304L SS weld metal on its corrosion behavior in simulated groundwater, for its application as a canister material for long-term storage of nuclear vitrified high-level waste in geological repositories. AISI type 304L SS weld pad was fabricated by multipass gas tungsten arc welding process using 308L SS filler wire. The as-welded specimens were subsequently subjected to carbide nucleation and further to LTS at 500 °C for 11 days to simulate a temperature of 300 °C for 100-year life of the canister in geological repositories. Delta ferrite ( δ-ferrite) content of the 304L SS weld metal substantially decreased on carbide nucleation treatment and further only a marginal decrease occurred on LTS treatment. The microstructure of the as-welded consisted of δ-ferrite as a minor phase distributed in austenite matrix. The δ-ferrite appeared fragmented in the carbide-nucleated and LTS-treated weld metal. The degree of sensitization measured by double-loop electrochemical potentokinetic reactivation method indicated an increase in carbide nucleation treatment when compared to the as-welded specimens, and further increase occurred on LTS treatment. Potentiodynamic anodic polarization investigations in simulated groundwater indicated a substantial decrease in the localized corrosion resistance of the carbide-nucleated and LTS 304L SS weld metals, when compared to the as-welded specimens. Post-experimental micrographs indicated pitting as the primary mode of attack in the as-welded, while pitting and intergranular corrosion (IGC) occurred in the carbide-nucleated weld metal. LTS-treated weld metal predominantly underwent IGC attack. The decrease in the localized corrosion resistance of the weld metal after LTS treatment was found to have a direct correlation with the degree of sensitization and the weld microstructure. The results are detailed in the manuscript.

  3. Effect of Low-Temperature Sensitization on the Corrosion Behavior of AISI Type 304L SS Weld Metal in Simulated Groundwater

    Science.gov (United States)

    Suresh, Girija; Nandakumar, T.; Viswanath, A.

    2018-04-01

    The manuscript presents the investigations carried out on the effect of low-temperature sensitization (LTS) of 304L SS weld metal on its corrosion behavior in simulated groundwater, for its application as a canister material for long-term storage of nuclear vitrified high-level waste in geological repositories. AISI type 304L SS weld pad was fabricated by multipass gas tungsten arc welding process using 308L SS filler wire. The as-welded specimens were subsequently subjected to carbide nucleation and further to LTS at 500 °C for 11 days to simulate a temperature of 300 °C for 100-year life of the canister in geological repositories. Delta ferrite (δ-ferrite) content of the 304L SS weld metal substantially decreased on carbide nucleation treatment and further only a marginal decrease occurred on LTS treatment. The microstructure of the as-welded consisted of δ-ferrite as a minor phase distributed in austenite matrix. The δ-ferrite appeared fragmented in the carbide-nucleated and LTS-treated weld metal. The degree of sensitization measured by double-loop electrochemical potentokinetic reactivation method indicated an increase in carbide nucleation treatment when compared to the as-welded specimens, and further increase occurred on LTS treatment. Potentiodynamic anodic polarization investigations in simulated groundwater indicated a substantial decrease in the localized corrosion resistance of the carbide-nucleated and LTS 304L SS weld metals, when compared to the as-welded specimens. Post-experimental micrographs indicated pitting as the primary mode of attack in the as-welded, while pitting and intergranular corrosion (IGC) occurred in the carbide-nucleated weld metal. LTS-treated weld metal predominantly underwent IGC attack. The decrease in the localized corrosion resistance of the weld metal after LTS treatment was found to have a direct correlation with the degree of sensitization and the weld microstructure. The results are detailed in the manuscript.

  4. Thermal stir welding process

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2012-01-01

    A welding method is provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  5. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  6. Review of Welding Terminology

    Directory of Open Access Journals (Sweden)

    Angelika Petrėtienė

    2011-04-01

    Full Text Available The paper discusses welding terms in accordance with the Lithuanian standard LST EN 1792 „Welding. The multilingual list of welding terms and similar processes”, „The Russian–Lithuanian dictionary of the terms of mechanical engineering technology and welding“ and the examples from postgraduates‘ final works. It analyses the infringement of lexical, word-building and morphological rules. First-year students should already be familiar with the standardized terms of their speciality. More active propagation of the terms should help to avoid terminology mistakes in various scientific spheres.

  7. Half bead welding technique

    International Nuclear Information System (INIS)

    Canonico, D.A.; Holz, P.P.

    1978-05-01

    The ORNL has employed the Section XI half-bead procedure for six repair welds. Table 2 identifies the repairs and the components upon which they were accomplished. The weld repairs were performed to permit us to evaluate material properties, residual stresses, weld repair procedures, and structural behavior of repaired pressure vessels. As a consequence of our study we concluded that when the half bead procedure is correctly applied: (1) there is no metallurgical degradation of the base material, (2) residual stresses of yield point magnitude will be present, and (3) the structural integrity of the pressure vessel is not impaired at Charpy V-notch upper shelf temperatures

  8. Mechanical properties and long-range behaviour of TZM-welding joints

    International Nuclear Information System (INIS)

    Jakobeit, W.; Eck, R.; Ullrich, G.

    1987-01-01

    In order to utilize the known excellent high temperature properties of TZM (Mo-0,5Ti-0,08Zr) for construction of components with thick sections (sheets of 8 mm wall thickness, bars of 25 mm diameter) the testing of suitable joining techniques was necessary. Based on the present state of the art the EB- and TIG-welding as well as the friction welding seemed to be the qualified methods. The investigations of the welded specimens covered non-destructive tests and metallographic evaluations as well as tensile tests, long term creep rupture tests at 850 0 C and fatigue tests unter tension-compression stresses at room temperature and 850 0 C. EB- and TIG-weldments showed coarse grained weld and heat affected zones. Due to higher gas contents, the EB-welded specimens produced by P/M process were interspersed with pores while the joints of the ARC-cast TZM material were uniform. However, TIG-welds of both variants were affected with porosity and cracks. The friction welds were almost perfect. In the tensile tests, all the joints containing recrystallized microstructure zones ruptured in the welds at strength values equivalent to recrystallized TZM. The strength of friction welds exhibited significant higher values. At room temperature the tensile ductility of all weldments was inadequate, the friction welded specimens showed the lowest values. At 850 0 C the tensile ductility was adequate in all variants. The creep rupture tests at 850 0 C exhibit up to 10 000 h that the strength of the friction weldments exceed those of the EB-weldments. (orig./IHOE) [de

  9. High-energy-beam welding of type 316LN stainless steel for cryogenic applications

    International Nuclear Information System (INIS)

    Siewert, T.A.; Gorni, D.; Kohn, G.

    1988-01-01

    Laser and electron beam welds in 25-mm-thick AISI 316LN specimens containing 0.16 wt.$% N were evaluated for fusion reactor applications and their mechanical properties were compared with those of welds generated by lower productivity processes such as shielded-metal-arc and gas-metal-arc welding. Tensile tests were performed on transverse tensile specimens at 4 K. For both welding processes the fractures occurred in the base metal at a strength level near 950 MPa. This indicated that the weld and heat affected zone had a strength similar to that of the base metal. The 4 K weld fracture toughness was only slightly less than that for the base metal and comparable to the best values achieved with conventional welding processes in 316Ln weld metal. The Charpy V-notch absorbed energies averaged near 70 J at 76 K. Metallographic analysis revealed cellular and fully austenitic solidification with little porosity and no evidence of hot cracking

  10. Reduction method for residual stress of welded joint using harmonic vibrational load

    International Nuclear Information System (INIS)

    Aoki, Shigeru; Nishimura, Tadashi; Hiroi, Tetsumaro; Hirai, Seiji

    2007-01-01

    Welding is widely used for construction of many structures. Since welding is a process using locally given heat, residual stress is generated near the bead. Tensile residual stress degrades fatigue strength. Some reduction methods of residual stress have been presented and, for example, heat treatment and shot peening are practically used. However, those methods need special tools and are time consuming. In this paper, a new method for reduction of residual stress using harmonic vibrational load during welding is proposed. The proposed method is examined experimentally for some conditions. Two thin plates are supported on the supporting device and butt-welded using an automatic CO 2 gas shielded arc welding machine. Residual stress in the direction of the bead is measured by using a paralleled beam X-ray diffractometer with scintillation counter after removing quenched scale chemically. First, the welding of rolled steel for general structure for some excitation frequencies is examined. Specimens are welded along the groove on both sides. For all frequencies, tensile residual stress near the bead is significantly reduced. Second, welding of the specimen made of high tensile strength steel is examined. In this case, tensile residual stress near the bead is also reduced. Finally, the proposed method is examined by an analytical method. An analytical model which consists of mass and preloaded springs with elasto-plastic characteristic is used. Reduction of residual stress is demonstrated using this model

  11. Welding distortion analysis of multipass joint combination with different sequences using 3D FEM and experiment

    International Nuclear Information System (INIS)

    Manurung, Yupiter H.P.; Lidam, Robert Ngendang; Rahim, M. Ridzwan; Zakaria, M. Yusof; Redza, M. Ridhwan; Sulaiman, M. Shahar; Tham, Ghalib; Abas, Sunhaji K.

    2013-01-01

    This paper presents an investigation of the welding sequence effect on induced angular distortion using FEM and experiments. The specimen of a combined joint geometry was modeled and simulated using Multipass Welding Advisor (MWA) in SYSWELD 2010 based on the thermal-elastic-plastic approach with low manganese carbon steel S3355J2G3 as specimen material and Goldak's double ellipsoid as heat source model. To validate the simulation results, a series of experiments was conducted with two different welding sequences using automated welding process, low carbon steel as parent metal, digital GMAW power source with premixed shielding gas and both-sided clamping technique. Based on the results, it was established that the thermo-elastic-plastic 3D FEM analysis shows good agreement with experimental results and the welding sequence “from outside to inside” induced less angular distortion compared to “from inside to outside”. -- Highlights: • 3D FEM was used to analyze the welding distortion on two different sequences. • Simulation results were validated with experiments using automated welding system. • Simulation results and experiments showed acceptable accuracy. • Welding sequence “outside–inside” showed less distortion than “inside–outside”

  12. Fracture toughness and crack growth resistance of pressure vessel plate and weld metal steels

    International Nuclear Information System (INIS)

    Moskovic, R.

    1988-01-01

    Compact tension specimens were used to measure the initiation fracture toughness and crack growth resistance of pressure vessel steel plates and submerged arc weld metal. Plate test specimens were manufactured from four different casts of steel comprising: aluminium killed C-Mn-Mo-Cu and C-Mn steel and two silicon killed C-Mn steels. Unionmelt No. 2 weld metal test specimens were extracted from welds of double V butt geometry having either the C-Mn-Mo-Cu steel (three weld joints) or one particular silicon killed C-Mn steel (two weld joints) as parent plate. A multiple specimen test technique was used to obtain crack growth data which were analysed by simple linear regression to determine the crack growth resistance lines and to derive the initiation fracture toughness values for each test temperature. These regression lines were highly scattered with respect to temperature and it was very difficult to determine precisely the temperature dependence of the initiation fracture toughness and crack growth resistance. The data were re-analysed, using a multiple linear regression method, to obtain a relationship between the materials' crack growth resistance and toughness, and the principal independent variables (temperature, crack growth, weld joint code and strain ageing). (author)

  13. Microstructure Stability During Creep of Friction Stir Welded AA2024-T3 Alloy

    Science.gov (United States)

    Regev, Michael; Rashkovsky, Tal; Cabibbo, Marcello; Spigarelli, Stefano

    2018-01-01

    The poor weldability of the AA2024 aluminum alloy limits its use in industrial applications. Because friction stir welding (FSW) is a non-fusion welding process, it seems to be a promising solution for welding this alloy. In the current study, FSW was applied to butt weld AA2024-T3 aluminum alloy plates. Creep tests were conducted at 250 and at 315 °C on both the parent material and the friction stir welded specimens. The microstructures of the welded and non-welded AA2024-T3 specimens before and after the creep tests were studied and compared. A comprehensive transmission electron microscopy study together with a high-resolution scanning electron microscopy study and energy-dispersive x-ray spectroscopy analysis was conducted to investigate the microstructure stability. The parent material seems to contain two kinds of Cu-rich precipitates—coarse precipitates of a few microns each and uniformly dispersed fine nanosized precipitates. Unlike the parent material, the crept specimens were found to contain the two kinds of precipitates mentioned above together with platelet-like precipitates. In addition, extensive decoration of the grain boundaries with precipitates was clearly observed in the crept specimens. Controlled aging experiments for up to 280 h at the relevant temperatures were conducted on both the parent material and the welded specimens in order to isolate the contribution of exposure to high temperatures to the microstructure changes. TEM study showed the development of dislocation networks into a cellular dislocation structure in the case of the parent metal. Changes in the dislocation structure as a function of the creep strain and the FSW process were recorded. A detailed creep data analysis was conducted, taking into account the instability of the microstructure.

  14. Temper-bead repair-welding of neutron-irradiated reactor (pressure) vessel by low-heat-input TIG and YAG laser welding

    International Nuclear Information System (INIS)

    Nakata, Kiyotomo; Ozawa, Masayoshi; Kamo, Kazuhiko

    2006-01-01

    Weldability in neutron-irradiated low alloy steel for reactor (pressure) vessel has been studied by temper-bead repair-welding of low-heat-input TIG and YAG laser welding. A low alloy steel and its weld, and stainless steel clad and nickel (Ni)-based alloy clad were irradiated in a materials test reactor (LVR-15, Czech Republic) up to 1.4 x 10 24 n/m 2 (>1 MeV) at 290degC, which approximately corresponds to the maximum neutron fluence of 60-year-operation plants' vessels. The He concentration in the irradiated specimens was estimated to be up to 12.9 appm. The repair-welding was carried out by TIG and YAG laser welding at a heat input from 0.06 to 0.86 MJ/m. The mechanical tests of tensile, impact, side bend and hardness were carried out after the repair-welding. Cracks were not observed in the irradiated low alloy steel and its weld by temper-bead repair-welding. Small porosities were formed in the first and second layers of the repair-welds of low alloy steel (base metal). However, only a few porosities were found in the repair-welds of the weld of low alloy steel. From the results of mechanical tests, the repair-welding could be done in the irradiated weld of low alloy steel containing a He concentration up to 12.9 appm, although repair-welding could be done in base metal of low alloy steel containing up to only 1.7 appmHe. On the other hand, cracks occurred in the heat affected zones of stainless steel and Ni-based alloy clads by repair-welding, except by YAG laser repair-welding at a heat input of 0.06 MJ/m in stainless steel clad containing 1.7 appmHe. Based on these results, the determination processes were proposed for optimum parameters of repair-welding of low alloy steel and clad used for reactor (pressure) vessel. (author)

  15. Recent developments in pipeline welding practice

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Fourteen chapters are included: overview of pipeline welding systems and quality assurance, CRC automatic welding system, H.C. Price Co. automatic welding system, semi-automatic MIG-welding process, partial penetration welding of steel pipes for gas distribution, construction procedures and quality control in offshore pipeline construction, welding in repair and maintenance of gas transmission pipelines, British Gas studies of welding on pressurized gas transmission pipelines, hot tapping pipelines, underwater welding for offshore pipelines and associated equipment, radial friction welding, material composition vs weld properties, review of NDT of pipeline welds, and safety assurance in pipeline construction. A bibliography of approximately 150 references is included, arranged according to subject and year.

  16. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  17. Residual stress by repair welds

    International Nuclear Information System (INIS)

    Mochizuki, Masahito; Toyoda, Masao

    2003-01-01

    Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

  18. An Investigation on the Influence of Root Defects on the Fatigue Life of the Welded Structure of a Large Two-Stroke Diesel Engine

    DEFF Research Database (Denmark)

    Hansen, Anders V.; Olesen, John Forbes; Agerskov, Henning

    2004-01-01

    -models of the welded joints, are described and the results presented. In addition, large-scale test specimens with controlled lack-of-fusion weld root geometry were manufactured and fatigue tested to develop S-N curves and determine threshold stress intensity factor range values. These were established for opening......The crankshaft housings of large two-stroke diesel engines are welded structures subjected to constant amplitude loading and designed for infinite life at full design load. A new design of the so-called frame box has been introduced in the engine using butt welded joints of thick plates, welded...

  19. Welding of refractory alloys

    International Nuclear Information System (INIS)

    Lessmann, G.G.

    1984-01-01

    This review primarily summarizes welding evaluations supported by NASA-Lewis Research Center in the 1960s. A literature search run in preparation for this review indicates that more recent work is modest by comparison. Hence, this review restates these accomplishments briefly and addresses opportunities which have evolved in welding technology (such as lasers) in the intervening decade. Emphasis in this review is given to tantalum- and niobium-base alloys. Considerable work was also done to assure that a consistent comparison was made with tungsten. A wide variety of candidate alloys derived primarily from developments directed at aircraft propulsion applications were available. Early efforts by NASA were directed at screening studies to select promising structural alloys for the space power application. This objective required fine tuning of welding procedures, e.g., the demonstration of stringent standards for control of welding atmosphere to assure good corrosion resistance in liquid alkali metals. 16 figures, 6 tables

  20. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...

  1. Friction stir welding tool

    Science.gov (United States)

    Tolle,; Charles R. , Clark; Denis E. , Barnes; Timothy, A [Ammon, ID

    2008-04-15

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  2. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...

  3. A Probabilistic Damage Tolerance Concept for Welded Joints

    DEFF Research Database (Denmark)

    Lassen, T.; Sørensen, John Dalsgaard

    2002-01-01

    The present paper presents the necessary crack growth statistics and suggests stochastic models for a reliability analysis of the fatigue fracture of welded steel plate joints. The reliability levels are derived from extensive testing with fillet-welded joints for which the entire crack growth...... history has been measured, not only the final fatigue life. The statistics for the time to reach given crack depths are determined. Fracture-mechanics-derived crack growth curves are fitted to the measured experimental curves and the best fit defines the growth parameters involved for each test specimen...

  4. Modeling the damage of welded steel, using the GTN model

    Directory of Open Access Journals (Sweden)

    El-Ahmar Kadi

    2014-11-01

    Full Text Available The aim of our work is the modeling of the damage in the weld metal according to the finite element method and the concepts of fracture mechanics based on local approaches using the code ABAQUS calculates. The use of the Gurson-Tvergaard-Needleman model axisymmetric specimens AE type to three different zones (Base metal, molten metal and heat affected Zone with four levels of triaxiality (AE2, AE4, AE10 and AE80, we have used to model the behavior of damage to welded steel, which is described as being due to the growth and coalescence of cavities with high rates of triaxiality

  5. CT appearances of emphysema and clinical application

    International Nuclear Information System (INIS)

    Wang Xinlian; Ma Daqing; Chen Budong; He Wen; Guan Yansheng; Zhang Yansong; Tang Hongqu; Wang Zhenguang

    2006-01-01

    Objective: To investigate CT appearances of different types of emphysema and to determine the clinic value for differential diagnosis. Methods: Twenty-three specimens with emphysema selected from 33 autopsy specimens were included in this study. All specimens were inflated and fixed by Heitzman's method, then examined by spiral CT scan. The CT appearances of different types of emphysema in every specimen were analyzed. After the specimens were cut into 10 mm thickness slices, the CT- pathologic correlation was done. Fifteen clinical cases confirmed by pathology or clinical process were all performed spiral CT scan and analyzed, including emphysema-accompanying pneumonia 11 cases, emphysema-accompanying nodule 4 cases. Result: Centriacinar emphysema (CAE)can be seen in 21 of 23 specimens, pancinar emphysema(PAE) can be seen in 5 of 23 specimens, all coexisting with CAE. Distal acinar emphysema(DAE) can be seen in 19 of 23 specimens, irregular emphysema can be seen in 3 of 23 specimens. In all specimens, emphysema can be seen in bilateral lung fields, distributing similarly. Seventeen of 23 eases (17/23) showed no less than two types of emphysema. Fourteen cases of emphysema- accompanying pneumonia (clinic: 11 cases, specimen: 3 cases) showed 'pseudocavity' or 'pseudohoneycombing' (emphysema lesion that had not been filled in the consolidation). Four eases of emphysema-accompanying nodule showed 'pseudopleuralhollow' (wall of DAE or bulla connecting with nodule). Conclusion: The CT manifestations of emphysema, the characteristics of distribution and multi- type of emphysema coexisting can help differentiate cystic air space diseases. The characteristics of complications of emphysema, the 'pseudocavity', 'pseudohoneycombing' and 'pseudopleuralhollow', may be help for differential diagnosis. (authors)

  6. Underwater Welding Techniques

    OpenAIRE

    Esam F. Alajmi; Ahmad A. Alqenaei

    2017-01-01

    Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as well as increasing in the marine transportation and industrial applications. Applications of underwater welding well be increased in Kuwait in the coming years due to the strategic directive of the country toward starting the offshore oil and gas exploration and production, and the increase in marine transportation projects. Therefore, there is a need to understand the concept of u...

  7. Splitting tests on rock specimens

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J D; Stagg, K G

    1970-01-01

    Splitting tests are described for a square-section sandstone specimens line loaded through steel or timber packings on the top face and supported on the bottom face either on similar packings (type A specimen) or directly on the lower platen plate of the testing machine (type B specimens). The stress distribution across the vertical central plane and the horizontal central plane were determined from a linear elastic finite element analysis for both types. Two solutions were obtained for the type B specimen: one assuming no friction between the base of the specimen and the platen plate and the other assuming no relative slip between the surfaces. Vertical and horizontal strains were measured at the center of the specimens for all loads up to failure.

  8. Flexural strength of pure Ti, Ni-Cr and Co-Cr alloys submitted to Nd:YAG laser or TIG welding.

    Science.gov (United States)

    Rocha, Rick; Pinheiro, Antônio Luiz Barbosa; Villaverde, Antonio Balbin

    2006-01-01

    Welding of metals and alloys is important to Dentistry for fabrication of dental prostheses. Several methods of soldering metals and alloys are currently used. The purpose of this study was to assess, using the flexural strength testing, the efficacy of two processes Nd:YAG laser and TIG (tungsten inert gas) for welding of pure Ti, Co-Cr and Ni-Cr alloys. Sixty cylindrical specimens were prepared (20 of each material), bisected and welded using different techniques. Four groups were formed (n=15). I: Nd:YAG laser welding; II- Nd:YAG laser welding using a filling material; III- TIG welding and IV (control): no welding (intact specimens). The specimens were tested in flexural strength and the results were analyzed statistically by one-way ANOVA. There was significant differences (pTIG and laser welding and also between laser alone and laser plus filling material. In conclusion, TIG welding yielded higher flexural strength means than Nd:YAG laser welding for the tested Ti, Co-Cr and Ni-Cr alloys.

  9. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  10. Effect of sized and specimen geometry on the initiation and propagation of the ductile fracture

    International Nuclear Information System (INIS)

    Frund, J.M.; Marini, B.; Bethmont, M.

    1994-02-01

    Strength to the fracture of the pipe in PWR has to be justified with mechanical analyses. These tests are based on the strength to ductile fracture of steels which are tested in lab. The values of resistance to fracture are obtained through tensile tests on CT specimens (determination of J-R curves). The purpose of this study is to justify the sizes of the specimens which have to be used to characterize the strength to ductile fracture of steel in secondary pipes. Tests were conducted on 0,5T-CT, 1T-CT and 2T-CT specimens. Two materials with different suffer contents were studied. The test results show that the JO,2 values gotten from the different specimens are similar. But the strength to ductile fracture in 2T-CT specimens in lower than the one measured in 0,5t-CT and 1T-CT specimens. The surface of fracture of the different specimens displays splits perpendicular to the notch and parallel to the sheet surface. These splits are produced by the separation of the manganese sulfur inclusions. The effect notes on the J-R curves seems to be relevant to these splits. The reason why these splits might be responsible for a decrease of the tearing modulus are not clearly defined up to this point. The results which have been published show the importance of the geometry effects (presence or not of lateral notches...) and the loading mode on the strength to ductile fracture. We note that the curves determined from tests on CT specimens are conservative. A few preliminary studies showed that the geometry effects on resistance to fracture can be studied and explained by using local approach methods. The Rousselier modeling is useful to explain the behaviour of ferritic steels in ductile fracture. (authors). 20 refs., 7 figs., 5 tabs

  11. Effects of the Heterogeneity in the Electron Beam Welded Joint on Mechanical Properties of Ti6Al4V Alloy

    Science.gov (United States)

    Liu, Jing; Gao, Xiao-Long; Zhang, Lin-Jie; Zhang, Jian-Xun

    2015-01-01

    The aim of this investigation was to evaluate the effect of microstructure heterogeneity on the tensile and low cycle fatigue properties of electron beam welded (EBW) Ti6Al4V sheets. To achieve this goal, the tensile and low cycle fatigue property in the EBW joints and base metal (BM) specimens is compared. During the tensile testing, digital image correlation technology was used to measure the plastic strain field evolution within the specimens. The experimental results showed that the tensile ductility and low cycle fatigue strength of EBW joints are lower than that of BM specimens, mainly because of the effect of microstructure heterogeneity of the welded joint. Moreover, the EBW joints exhibit the cyclic hardening behavior during low fatigue process, while BM specimens exhibit the cyclic softening behavior. Compared with the BM specimens with uniform microstructure, the heterogeneity of microstructure in the EBW joint is found to decrease the mechanical properties of welded joint.

  12. Shear punch testing as a tool for evaluating welded pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, G.R.; Elwazri, A.; Varano, R.; Yue, S.; Jonas, J.J. [McGill Univ., Montreal, PQ (Canada). Dept. of Metals and Materials Engineering; Pokutylowicz, N. [ExxonMobil Research and Engineering Co., Annandale, NJ (United States)

    2005-07-01

    This study examined the mechanical properties across a welded joint in a 35 mm steel pipe. Results were compared with microhardness measurements. The chemical composition of the 4130 steel and welding wire included carbon, manganese, silicon, nickel, chromium and molybdenum. The thermal cycles experienced during welding can result in differences in the grain size, phase, composition and morphology of precipitates. These thermal cycles can upset the balance of high strength and good toughness in steels, producing poor toughness in the heat-affected zone (HAZ). In the shear punch test, a flat-ended cylindrical punch was used to produce a 3 mm diameter disk from a sheet specimen with a recommended thickness of 300 to 350 {mu}m. The shear punch test provided tensile property data with only a very small amount of material, which is ideal for testing welds. It also provides full tensile data (yield strength, ultimate tensile strength and elongation) which are not specifically provided by hardness testing. Shear punch techniques can also improve the across-weld resolution of tensile testing. The results showed that the changes in strength properties across the weld were consistent with the microhardness measurements. The change in elongation across the weld joint was successfully measured using the punch test method. The HAZ in the welded joint in this study had a good combination of high strength and ductility, while the weld bead had moderate strength and relatively low ductility. 7 refs., 1 tab., 9 figs.

  13. Effects of stop–start features on residual stresses in a multipass austenitic stainless steel weld

    International Nuclear Information System (INIS)

    Turski, M.; Francis, J.A.; Hurrell, P.R.; Bate, S.K.; Hiller, S.; Withers, P.J.

    2012-01-01

    In this article we describe experiments that characterise and quantify the localised perturbations in residual stress associated with both ramped and abrupt stop–start features in a multipass weld. Residual stress distributions in AISI Grade 304L/308L stainless steel groove-welded specimens, containing weld interruptions that were introduced in a controlled manner, have been characterised using both neutron diffraction and the incremental deep hole drilling method. The extent to which the localised stresses associated with the interruptions were annealed by overlayed passes was also assessed. The results suggest that, regardless of the type of interruption, there can be significant localised increases in residual stress if the stop–start feature is left exposed. If further weld passes are deposited, then the localised increases in stress are likely to persist if the interruption was abrupt, whereas for a ramped interruption they may be dissipated. - Highlights: ► In this study the residual stress-field surrounding weld interruptions was measured. ► Localised stresses were found to increase at weld interruptions. ► Both ramped and abrupt weld interruptions were investigated. ► After subsequent weld passes, localised stresses persisted for abrupt interruptions. ► After subsequent weld passes, localised stresses dissipated for ramped interruptions.

  14. Creep strength of hastelloy X TIG-welded cylinder under internal pressure at elevated temperature

    International Nuclear Information System (INIS)

    Udoguchi, Teruyoshi; Indo, Hirosato; Isomura, Kazuyuki; Kobatake, Kiyokazu; Nakanishi, Tsuneo.

    1981-01-01

    Creep tests on circumferentially TIG-welded Hastelloy x cylinders were carried out under internal pressure for the investigation of structural behavior of welded components in high temperature environment. The creep rupture strength of TIG-welded cylinders was much lower than that of non-welded cylinders, while such reduction was not found in uniaxial creep tests on TIG-welded bars. It was deduced that the reduction was due to the low ductility (ranging from 1 to 5%) of the weld metal to which enhanced creep was induced by the adjacent base metal whose creep strain rate was much higher than that of the weld metal. Therefore, uniaxial creep tests on bar specimens is not sufficient for proper assessment of the creep rupture strength of welded components. Both creep strain rate and creep ductility should be concerned for the assessment. Creep tests by using components such as cylinder under internal pressure are recommendable for the confirmation of creep strength of welded structures and components. (author)

  15. Automatic welding machine for piping

    International Nuclear Information System (INIS)

    Yoshida, Kazuhiro; Koyama, Takaichi; Iizuka, Tomio; Ito, Yoshitoshi; Takami, Katsumi.

    1978-01-01

    A remotely controlled automatic special welding machine for piping was developed. This machine is utilized for long distance pipe lines, chemical plants, thermal power generating plants and nuclear power plants effectively from the viewpoint of good quality control, reduction of labor and good controllability. The function of this welding machine is to inspect the shape and dimensions of edge preparation before welding work by the sense of touch, to detect the temperature of melt pool, inspect the bead form by the sense of touch, and check the welding state by ITV during welding work, and to grind the bead surface and inspect the weld metal by ultrasonic test automatically after welding work. The construction of this welding system, the main specification of the apparatus, the welding procedure in detail, the electrical source of this welding machine, the cooling system, the structure and handling of guide ring, the central control system and the operating characteristics are explained. The working procedure and the effect by using this welding machine, and the application to nuclear power plants and the other industrial field are outlined. The HIDIC 08 is used as the controlling computer. This welding machine is useful for welding SUS piping as well as carbon steel piping. (Nakai, Y.)

  16. Application of eddy current inversion technique to the sizing of defects in Inconel welds with rough surfaces

    International Nuclear Information System (INIS)

    Yusa, Noritaka; Machida, Eiji; Janousek, Ladislav; Rebican, Mihai; Chen, Zhenmao; Miya, Kenzo

    2005-01-01

    This paper evaluates the applicability of eddy current inversion techniques to the sizing of defects in Inconel welds with rough surfaces. For this purpose, a plate Inconel weld specimen, which models the welding of a stub tube in a boiling water nuclear reactor is fabricated, and artificial notches machined into the specimen. Eddy current inspections using six different eddy current probes are conducted and efficiencies were evaluated for the six probes for weld inspection. It is revealed that if suitable probes are applied, an Inconel weld does not cause large noise levels during eddy current inspections even though the surface of the weld is rough. Finally, reconstruction of the notches is performed using eddy current signals measured using the uniform eddy current probe that showed the best results among the six probes in this study. A simplified configuration is proposed in order to consider the complicated configuration of the welded specimen in numerical simulations. While reconstructed profiles of the notches are slightly larger than the true profiles, quite good agreements are obtained in spite of the simple approximation of the configuration, which reveals that eddy current testing would be an efficient non-destructive testing method for the sizing of defects in Inconel welds

  17. Applicability of eddy current inversion techniques to the sizing of defects in Inconel welds of BWR internals

    International Nuclear Information System (INIS)

    Yusa, Noritaka; Janousek, Ladislav; Rebican, Mihai; Chen, Zhenmao; Miya, Kenzo; Machida, Eiji

    2004-01-01

    This paper evaluates the applicability of eddy current inversion techniques to the sizing of defects in Inconel welds with rough surfaces. For this purpose, a plate Inconel weld specimen, which models the welding of a stub tube in a boiling water nuclear reactor, is fabricated, and artificial notches machined into the specimen. Eddy current inspections using six probes in weld inspection evaluated. It is revealed that if suitable probes are applied, an Inconel weld does not provide large noise signals in eddy current inspections even though the surface of the weld is rough. Finally, reconstruction of the notches are performed using eddy current signals measured with the use of the uniform eddy current probe that showed the best results among the six probes in the inspection. A simplified configuration is proposed in order to consider the complicated configuration of the welded specimen in numerical simulations. While reconstructed profiles of the notches are slightly larger than the true profiles, quite good agreements are obtained in spite of the simple approximation of the configuration, which reveals that eddy current testing would be an efficient non-destructive testing method for the sizing of defects in Inconel welds. (author)

  18. Influence of the phase morphology on the weldability of PLA/PBAT-blends by using butt-welding

    Science.gov (United States)

    Goebel, L.; Bonten, C.

    2014-05-01

    The material development in the field of bioplastics is steadily increasing. It is important to examine the processability but the Investigation of further process steps is also very important. In this paper the weldability of bioplastics is discussed. Compounds of Polylactide (PLA) and Polybutyleneadipate-terephthalate (PBAT) are produced by a twin screw extruder with different mixing ratios. Tensile specimens are produced by injection moulding and the tensile tests are carried out. In order to verify the weldability, some tensile specimens are cut in halfes and butt welded. Afterwards a tensile test is performed with the welded samples and the results are compared with the values of the unwelded samples. For understanding the results, the morphology of the welds were examined and correlated. It has been found that blends with a mixing ratio of 50:50 have the lowest welding factor, because of the immiscibility of PLA and PBAT. Weld images show segregated areas that reduce the force transmission.

  19. Effect of friction time on the microstructure and mechanic properties of friction welded AISI 1040/Duplex stainless steel

    Directory of Open Access Journals (Sweden)

    İhsan Kırık

    2000-06-01

    Full Text Available In this study, the effect on the characteristic microstructure and mechanic properties of friction time on the couple steels AISI 1040/AISI 2205 stainless steel joining with friction welding method was experimentally investigated. Friction welding experiment were carried out in privately prepared PLC controlled continuous friction welding machine by us. Joints were carried out under 1700 rpm rotation speed, with 30MPa process friction pressure, 60MPa forging pressure, 4 second forging pressure and under 3, 5, 7, 9 and 11 second friction time, respectively. After friction welding, the bonding interface microstructures of the specimens were examined by SEM microscopy and EDS analysis. After weld microhardness and tensile strength of specimens were carried out. The result of applied tests and observations pointed out that the properties of microstructure were changed with friction time increased. The excellent tensile strength of joint observed on 1700 rpm rotation speed and 3 second friction time sample.

  20. An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Cárcel-Carrasco

    2016-11-01

    Full Text Available This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite.

  1. Alternate Welding Processes for In-Service Welding

    Science.gov (United States)

    2009-04-24

    Conducting weld repairs and attaching hot tap tees onto pressurized pipes has the advantage of avoiding loss of service and revenue. However, the risks involved with in-service welding need to be managed by ensuring that welding is performed in a rep...

  2. Certification of a weld produced by friction stir welding

    Science.gov (United States)

    Obaditch, Chris; Grant, Glenn J

    2013-10-01

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  3. Ultrasonic inspection of austenitic welds

    International Nuclear Information System (INIS)

    Baikie, B.L.; Wagg, A.R.; Whittle, M.J.; Yapp, D.

    1976-01-01

    The ultrasonic examination of austenitic stainless steel weld metal has always been regarded as a difficult proposition because of the large and variable ultrasonic attenuations and back scattering obtained from apparently similar weld deposits. The work to be described shows how the existence of a fibre texture within each weld deposit (as a result of epitaxial growth through successive weld beads) produces a systematic variation in the ultrasonic attenuation coefficient and the velocity of sound, depending upon the angle between the ultrasonic beam and the fibre axis. Development work has shown that it is possible to adjust the welding parameters to ensure that the crystallographic texture within each weld is compatible with improved ultrasonic transmission. The application of the results to the inspection of a specific weld in type 316 weld metal is described

  4. Arc-weld pool interactions

    International Nuclear Information System (INIS)

    Glickstein, S.S.

    1978-08-01

    The mechanisms involved in arc-weld pool interactions are extremely complex and no complete theory is presently available to describe much of the phenomena observed during welding. For the past several years, experimental and analytical studies have been undertaken at the Bettis Atomic Power Laboratory to increase basic understanding of the gas tungsten arc welding process. These studies have included experimental spectral analysis of the arc in order to determine arc temperature and analytical modeling of the arc and weld puddle. The investigations have been directed toward determining the cause and effects of variations in the energy distribution incident upon the weldment. In addition, the effect of weld puddle distortion on weld penetration was investigated, and experimental and analytical studies of weld process variables have been undertaken to determine the effects of the variables upon weld penetration and configuration. A review of the results and analysis of these studies are presented

  5. Resistance Spot Welding of dissimilar Steels

    Directory of Open Access Journals (Sweden)

    Ladislav Kolařík

    2012-01-01

    Full Text Available This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA. Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.

  6. Mechanical evaluation of linear friction welds in titanium alloys through indentation experiments

    International Nuclear Information System (INIS)

    Corzo, M.; Casals, O.; Alcala, J.; Mateo, A.; Anglada, M.

    2005-01-01

    This article shows the results of a project that focuses on the characterization of the weld interface region of dissimilar joints between titanium alloys for aeronautical applications, specifically Ti-6Al-2Sn-4Zr-6Mo with Ti-6Al-4V, and Ti-6Al-2Sn-4Zr-6Mo with Ti-6Al-2Sn-4Zr-2Mo. The uniaxial flow stress and hardening response of the material containing the weld were analyzed following the finite elements simulations and mathematical formulations to correlate hardness and the amount of pile-up and sinking-in phenomena around sharp indenters with uniaxial mechanical properties. This allows to accurately stablishing the influence that welding process has on the mechanical response of the parts. Tests performed on these friction-welded specimens showed that the fine grained microstructures in the welds exhibited better properties than the base materials. (Author) 12 refs

  7. The effect of axial external magnetic field on tungsten inert gas welding of magnesium alloy

    Science.gov (United States)

    Li, Caixia; Zhang, Xiaofeng; Wang, Jing

    2018-04-01

    The influences of axial external magnetic field on the microstructure and mechanical property of the AZ31 magnesium (Mg) alloy joints were studied. The microstructure of Mg alloy joint consisted of the weld seam, heat affected zone and base metal zone. The average grain size of weld seam welded with magnetic field is 39 μm, which is 38% smaller than that of the joint welded with absence of magnetic field. And the microhardness of weld seam increases with the help of magnetic field treatment, owing to the coarse grain refinement. With coil current of 2.0A, the maximum mechanical property of joint increases 6.7% to 255 MPa over the specimen without magnetic field treatment. Furthermore, fracture location is near heat affected area and the fracture surface is characterized with ductile fracture.

  8. Material Characterization of Dissimilar Friction Stir Spot Welded Aluminium and Copper Alloy

    Science.gov (United States)

    Sanusi, K. O.; Akinlabi, E. T.

    2017-08-01

    In this research study, material characterization of dissimilar friction stir spot welded Aluminium and Copper was evaluated. Rotational speeds of 800 rpm and transverse speeds of 50 mm/min, 150 mm/min and 250 mm/min were used. The total numbers of samples evaluated were nine altogether. The spot welds were characterised by microstructure characterization using optical microscope (OEM) and scanning electron microscopy technique (SEM) by observing the evolution of the microstructure across the weld’s cross-section. lap-shear test of the of the spot weld specimens were also done. From the results, it shows that welding of metals and alloys using Friction stir spot welding is appropriate and can be use in industrial applications.

  9. Laser Welding of Coated Press-hardened Steel 22MnB5

    Science.gov (United States)

    Siltanen, Jukka; Minkkinen, Ari; Järn, Sanna

    The press-hardening process is widely used for steels that are used in the automotive industry. Using ultra-high-strength steels enables car manufacturers to build lighter, stronger, and safer vehicles at a reduced cost and generating lower CO2 emissions. In the study, laser welding properties of the coated hot stamped steel 22BMn5 were studied. A constant 900 °C temperature was used to heat the steel plates, and two different furnace times were used in the press-hardening, being 300 and 740 seconds. Some of the plates were shot blasted to see the influence of the partly removed oxide layer on the laser welding and quality. The welding set-up, welding, and testing of the weld specimens complied with the automotive testing code SEP 1220.

  10. Comparison of creep rupture behavior of tungsten inert gas and electron beam welded grade 91 steel

    International Nuclear Information System (INIS)

    Dey, H.C.; Vanaja, J.; Laha, K.; Bhaduri, A.K.; Albert, S.K.; Roy, G.G.

    2016-01-01

    Creep rupture behavior of Grade 91 steel weld joints fabricated by multi-pass tungsten inert gas (TIG) and electron beam welding (EBW) processes has been studied and compared with base metal. Cross-weld creep specimens were fabricated from the X-ray radiography qualified and post weld heat treated (760°C/4 h) weld joints. Creep testing of weld joints and base metal was carried out at 650°C over a stress range of 40°120 MPa. Creep life of EBW joint is comparable to base metal; whereas multi-pass TIG joint have shown significant drop in creep life tested for the same stress level. Both types of weld joints show Type IV cracking for all the stress levels. The steady state creep rate of multi-pass TIG is found to be fifteen times than that of EBW joint for stress level of 80 MPa, which may be attributed to over tempering, more re-austenization, and fine grain structure of inter-critical and fine grain heat affected zone regions of the TIG joint. In contrast, single-pass and rapid weld thermal cycles associated with EBW process causes minimum phase transformation in the corresponding regions of heat affected zone. Microstructure studies on creep tested specimens shows creep cavities formed at the primary austenite grain boundaries nucleated on coarse carbide precipitates. The hardness measured across the weld on creep tested specimens shows significant drop in hardness in the inter-critical and fine grain heat affected zone regions of multi-pass TIG (176 VHN) in comparison to 192 VHN in the corresponding locations in EBW joint. (author)

  11. Creep failure analysis of butt welded tubes

    International Nuclear Information System (INIS)

    Browne, R.J.; Parker, J.D.; Walters, D.J.

    1981-01-01

    As part of a major research programme to investigate the influence of butt welds on the life expectancy of tubular components, a series of internal-pressure, stress-rupture tests have been carried out. Thick walled 1/2Cr 1/2Mo 1/4V tube specimens were welded with mild steel, 1Cr 1/2Mo steel, 2 1/4Cr 1Mo steel or nominally matching 1/2Cr 1/2Mo 1/4V steel to give a wide range of weld metal creep strengths relative to the parent tube. The weldments were tested at 565 0 C at two values of internal pressure, and gave failure lives of up to 44,000 hrs. Finite element techniques have been used to determine the stationary state stress distribution in the weldment which was represented by a three material model. Significant stress redistribution was indicated and these results enabled the position and orientation of cracking and the rupture life to be predicted. The theoretical and experimental results have been used to highlight the limitations of current design methods which are based on the application of the mean diameter hoop stress to the parent material stress rupture data. (author)

  12. The influence of the heat treatment on delta ferrite transformation in austenitic stainless steel welds

    Directory of Open Access Journals (Sweden)

    B. Mateša

    2012-04-01

    Full Text Available Shielded metal arc (SMAW welded specimens using austenitic consumable materials with different amount of delta-ferrite are annealed in range 650-750 °C through 2-10 hours. Factorial plan 33 with influenced factors regression analyze of measured delta-ferrite values is used. The transformation i.e. decomposition of delta ferrite during annealing was analyzed regarding on weld cracking resistance using metallographic examination and WRC-1992 diagram.

  13. Re-analysis of fatigue data for welded joints using the notch stress approach

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard

    2010-01-01

    Experimental fatigue data for welded joints have been collected and subjected to re-analysis using the notch stress approach according to IIW recommendations. This leads to an overview regarding the reliability of the approach, based on a large number of results (767 specimens). Evidently......-welded joints agree quite well with the FAT 225 curve; however a reduction to FAT 200 is suggested in order to achieve approximately the same safety as observed in the nominal stress approach....

  14. Multipass autogenous electron beam welding

    International Nuclear Information System (INIS)

    Murphy, J.L.; Mustaleski, T.M. Jr.; Watson, L.C.

    1986-01-01

    A multipass, autogenous welding procedure was developed for 7.6 mm (0.3 in.) wall thickness Type 304L stainless steel cylinders. The joint geometry has a 1.5 mm (0.06 in.) root-face width and a rectangular stepped groove that is 0.762 mm (0.03 in.) wide at the top of the root face and extends 1.5 mm in height, terminating into a groove width of 1.27 mm which extends to the outside of the 1.27 mm high weld-boss. One weld pass is made on the root, three passes on the 0.762 mm wide groove and three passes to complete the weld. Multipass, autogenous, electron beam welds maintain the characteristic high depth-to-width ratios and low heat input of single-pass, electron beam welds. The increased part distortion (which is still much less than from arc processes) in multipass weldments is corrected by a preweld machined compensation. Mechanical properties of multipass welds compare well with single-pass welds. The yield strength of welds in aluminum alloy 5083 is approximately the same for single-pass or multipass electron beam and gas, metal-arc welds. The incidence and size of porosity is less in multipass electron beam welding of aluminum as compared to gas, metal-arc welds. The multipass, autogenous, electron beam welding method has proven to be a reliable way to make some difficult welds in multilayer parts or in an instance where inside part temperature or weld underbead must be controlled and weld discontinuities must be minimized

  15. Analysis of the Charpy V-notch test for welds

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    The ductile-brittle transition for a weld is investigated by numerical analyses of Charpy impact specimens. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation and the resulting thermal...... softening accounted for. The onset of cleavage is taken to occur when a critical value of the maximum principal stress is attained. The effect of weld strength undermatch or overmatch is investigated for a comparison material, and analyses are also carried out based on experimentally determined flow...... strength variations in a weldment in a HY100 steel. The predicted work to fracture shows a strong sensitivity to the location of the notch relative to the weld, with the most brittle behavior for a notch close to the narrow heat affected zone. The analyses illustrate the strong dependence of the transition...

  16. Designing aluminium friction stir welded joints against multiaxial fatigue

    Directory of Open Access Journals (Sweden)

    L. Susmel

    2016-07-01

    Full Text Available The present paper investigates the accuracy of the Modified Wöhler Curve Method (MWCM in estimating multiaxial fatigue strength of aluminium friction stir (FS welded joints. Having developed a bespoke joining technology, circumferentially FS welded tubular specimens of Al 6082-T6 were tested under proportional and non-proportional tension and torsion, the effect of non-zero mean stresses being also investigated. The validation exercise carried out using the experimental results have demonstrated that the MWCM applied in terms of nominal stresses, notch stresses, and also the Point Method is accurate in predicting the fatigue lifetime of the tested FS welded joints, with its use resulting in life estimates that fall within the uniaxial and torsional calibration scatter bands.

  17. Multiaxial fatigue of aluminium friction stir welded joints: preliminary results

    Directory of Open Access Journals (Sweden)

    D. G. Hattingh

    2015-07-01

    Full Text Available The aim of the present research is to check the accuracy of the Modified Wöhler Curve Method (MWCM in estimating the fatigue strength of friction stir (FS welded tubular joints of Al 6082-T6 subjected to in-phase and out-of-phase multiaxial fatigue loading. The welded samples being investigated were manufactured by equipping an MTS I-STIR process development system with a retracting tool that was specifically designed and optimised for this purpose. These specimens were tested under proportional and non-proportional tension and torsion, the effect of non-zero mean stresses being also investigated. The validation exercise carried out by using the generated experimental results allowed us to prove that the MWCM (applied in terms of nominal stresses is highly accurate in predicting the fatigue strength of the tested FS welded joints, its usage resulting in estimates falling with the uniaxial and torsional calibration scatter bands.

  18. Welding state of art for Eurofer 97 application to Tritium Blanket Module for ITER Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, P. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DM2S/DIR), 91 - Gif sur Yvette (France); Janin, F. [CEA Saclay, Dept. Modelisation de Systemes et Structures (DEN/DANS/DPC/SCP/Gerailp), 91 - Gif sur Yvette (France)

    2007-07-01

    stage. For TIG and laser processes, no metallurgical defect or damage has been observed. HAZ and Fusion Zones are larger in TIG welds compared with laser welds. Six TIG welding passes are necessary, compared to the two passes for laser process. For laser and Hybrid (MIG/Laser) welding process, joint coefficient can be considered as 1. All tensile specimens have broken outside the welds, and in the parent base material. For laser welds, tempering Post Welding Heat Treatment has markedly reduced the hardening level in fusion zone, to acceptable values in the range of 300 HV 10. Impact tests have shown good results. Welding simulation has been carried out, and numerical martensitic weld width is close to real one. (authors)

  19. Laser welding engineering

    International Nuclear Information System (INIS)

    Bhieh, N. M.; El Eesawi, M. E.; Hashkel, A. E.

    2007-01-01

    Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

  20. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  1. Welding. Performance Objectives. Basic Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a basic welding course. The materials were developed for a 36-week (2 hours daily) course developed to teach the fundamentals of welding shop work, to become familiar with the operation of the welding shop…

  2. Pulsed TIG welding of pipes

    International Nuclear Information System (INIS)

    Killing, U.

    1989-01-01

    The present study investigates into the effects of impulse welding parameters on weld geometry in the joint welding of thin-walled sheets and pipes (d=2.5 mm), and it uses random samples of thick-walled sheets and pipes (d=10 mm), in fixed positions. (orig./MM) [de

  3. Friction welding method

    International Nuclear Information System (INIS)

    Ishida, Ryuichi; Hatanaka, Tatsuo.

    1969-01-01

    A friction welding method for forming a lattice-shaped base and tie plate supporter for fuel elements is disclosed in which a plate formed with a concavity along its edge is pressure welded to a rotating member such as a boss by longitudinally contacting the projecting surfaces remaining on either side of the concavity with the rotating member during the high speed rotation thereof in the presence of an inert gas. Since only the two projecting surfaces of the plate are fused by friction to the rotary member, heat expansion is absorbed by the concavity to prevent distortion; moreover, a two point contact surface assures a stable fitting and promotes the construction of a rigid lattice in which a number of the abovementioned plates are friction welded between rotating members to form any desired complex arrangement. The inert has serves to protect the material quality of the contacting surfaces from air during the welding step. The present invention thus provides a method in which even Zircaloy may be friction welded in place of casting stainless steel in the construction of supporting lattices to thereby enhance neutron economy. (K. J. Owens)

  4. 46 CFR 57.04-1 - Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Test specimen requirements and definition of ranges... HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Procedure Qualification Range § 57.04-1 Test specimen requirements and definition of ranges (modifies QW 202, QW 210, QW 451, and QB 202...

  5. Computed Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

    Science.gov (United States)

    Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

    2005-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and is carried with the macro-flow of the weld metal. By using CT images, a 3-dimensional (3D) image of the lead flow pattern can be reconstructed. CT imaging was found to be a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

  6. Comparison of Metallurgical and Ultrasonic Inspections of Galvanized Steel Resistance Spot Welds

    International Nuclear Information System (INIS)

    Potter, Timothy J.; Ghaffari, Bita; Mozurkewich, George; Reverdy, Frederic; Hopkins, Deborah

    2006-01-01

    Metallurgical examination of galvanized steel resistance spot welds was used to gauge the capabilities of two ultrasonic, non-destructive, scanning techniques. One method utilized the amplitude of the echo from the weld faying surface, while the other used the spectral content of the echo train to map the fused area. The specimens were subsequently sectioned and etched, to distinguish the fused, zinc-brazed, and non-fused areas. The spectral maps better matched the metallurgical maps, while the interface-amplitude method consistently overestimated the weld size

  7. Improvement of Fatigue Life of Welded Structural Components of a Large Two-Stroke Diesel Engine by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; Hansen, Anders V.; Bjørnbak-Hansen, Jørgen

    2004-01-01

    one side only, with no access to the root side. Various investigations on the fatigue life of the structural components of this new design have been carried out. The present investigation concentrates on the improvement in fatigue life which may be obtained by grinding of the weld toes. The tests...... grinding to m=6 for the test series with grinding. In one of the test series, it was observed that in most cases crack initiation moved from the weld toe to the non-ground surface between the ground areas at the weld toes. Tests were made on steel S 275, on centrally and eccentrically loaded test specimens.......The crankshaft housings of large two-stroke diesel engines are welded structures subjected to constant amplitude loading and designed for infinite life at full design load. A new design of the so-called frame box has been introduced in the engine using butt weld joints of thick plates, welded from...

  8. Friction stir welding tool and process for welding dissimilar materials

    Science.gov (United States)

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  9. Characterization of laser welds in Al-10 wt.%Si coated ferritic stainless steel

    International Nuclear Information System (INIS)

    Kong, Jong Pan; Park, Tae Jun; Kim, Jeong Kil; Uhm, Sang Ho; Woo, In Su; Lee, Jong Sub; Park, Bong Gyu; Kang, Chung Yun

    2011-01-01

    409L stainless steel hot-dipped with Al-10 wt.%Si was welded using CO 2 laser and the microstructure and hardness of the weld were investigated. When the specimen was welded with laser power of 5 kW and welding speed of 5 m/min, full-penetrated sound weld was obtained. With that specimen, the relationship between the microstructure and hardness of the weld was examined. The hardness of the weld was the highest in the fusion zone (FZ) and decreased to the base metal (BM) via heat affected zone (HAZ). The hardness of the HAZ near bond line was also higher than that near the base metal. The maximum hardness in the fusion zone could be explained by the existence of the precipitates, that is, TiN, Ti(C,N), Al 2 O 3 and Al 2 O 3 + TiN mixed compounds with the size of 500 nm, and solution strengthening due to the elements Al and Si dissolved from the coating layer to the fusion zone. There were subgrains within the HAZ and more in the area near the bond line. In addition, fine TiC particles with the size under 50 nm was precipitated in the sub-grain boundaries. The formation of sub-grain boundaries and the particles precipitated in the boundaries might contributed to the high hardness in the HAZ.

  10. INVESTIGATION OF SINGLE-PASS/DOUBLE-PASS TECHNIQUES ON FRICTION STIR WELDING OF ALUMINIUM

    Directory of Open Access Journals (Sweden)

    N.A.A. Sathari

    2014-12-01

    Full Text Available The aim of this research is to study the effects of single-pass/ double-pass techniques on friction stir welding of aluminium. Two pieces of AA1100 with a thickness of 6.0 mm were friction stir welded using a CNC milling machine at rotational speeds of 1400 rpm, 1600 rpm and 1800 rpm respectively for single-pass and double-pass. Microstructure observations of the welded area were studied using an optical microscope. The specimens were tested by using a tensile test and Vickers hardness test to evaluate their mechanical properties. The results indicated that, at low rotational speed, defects such as ‘surface lack of fill’ and tunnels in the welded area contributed to a decrease in mechanical properties. Welded specimens using double-pass techniques show increasing values of tensile strength and hardness. From this investigation it is found that the best parameters of FSW welded aluminium AA1100 plate were those using double-pass techniques that produce mechanically sound joints with a hardness of 56.38 HV and 108 MPa strength at 1800 rpm compared to the single-pass technique. Friction stir welding, single-pass/ double-pass techniques, AA1100, microstructure, mechanical properties.

  11. The reliability of the repair weld joints of aged high temperature components in fossil power boilers

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Ohtani, Ryuichi [Kyoto Univ. (Japan); Fujii, Kazuya [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Yokoyama, Tomomitsu; Nishimura, Nobuhiko [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Suzuki, Komei [Japan Steel Works Ltd., Tokyo (Japan)

    1998-11-01

    It is of fundamental engineering importance to be able to give reliable assessments of the effective service life of the critical components used within fossil power plants, particularly for those operating for prolonged periods. It is common practice for such assessments to have been estimated using destructive tests, typically the stress rupture test, this having been recognized as one of the most reliable evaluation methods available. Its only drawback is that it often does not permit the component to be in use following the sampling of the test specimen without repairing. The current piece of work focuses on the reliability of the repair welds of components for specimens taken from fossil power plants, having been in service for prolonged periods. Several such repairs to welds have been made to an old power boiler, in particular to a superheater header which is fabricated from 2.25Cr-1Mo steel. Under close examination the repairs to the girth weldment showed susceptibilities of weld cracking, similar to that observed in as-manufactured material. Within the repaired region of the welded joint the microstructure, tensile properties and toughness seemed to be unaffected. The hardness attained its minimum value within the heat affected zone, HAZ of the repair weld, overlapping that of original girth weld HAZ. Furthermore, the stress rupture strength achieved its minimum value at the same position taking on the same value as the strength associated with the aged girth welded joint. (orig.)

  12. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    International Nuclear Information System (INIS)

    Kim, Kang Soo; Lee, Ho Jin; Woo, Wan Chuck; Seong, Baek Seok; Byeon, Jin Gwi; Park, Kwang Soo; Jung, In Chul

    2010-01-01

    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  13. Microstructural Effects on Hydrogen Delayed Fracture of 600 MPa and 800 MPa grade Deposited Weld Metal

    International Nuclear Information System (INIS)

    Kang, Hee Jae; Lee, Tae Woo; Cho, Kyung Mox; Kang, Namhyun; Yoon, Byung Hyun; Park, Seo Jeong; Chang, Woong Seong

    2012-01-01

    Hydrogen-delayed fracture (HDF) was analyzed from the deposited weld metals of 600-MPa and 800-MPa flux-cored arc (FCA) welding wires, and then from the diffusible hydrogen behavior of the weld zone. Two types of deposited weld metal, that is, rutile weld metal and alkali weld metal, were used for each strength level. Constant loading test (CLT) and thermal desorption spectrometry (TDS) analysis were conducted on the hydrogen pre-charged specimens electrochemically for 72 h. The effects of microstructures such as acicular ferrite, grain-boundary ferrite, and low-temperature-transformation phase on the time-to failure and amount of diffusible hydrogen were analyzed. The fracture time for hydrogen-purged specimens in the constant loading tests decreased as the grain size of acicular ferrite decreased. The major trapping site for diffusible hydrogen was the grain boundary, as determined by calculating the activation energies for hydrogen detrapping. As the strength was increased and alkali weld metal was used, the resistance to HDF decreased.

  14. Plasma Processes of Cutting and Welding

    Science.gov (United States)

    1976-02-01

    TIG process. 2.2.2 Keyhole Welding In plasma arc welding , the term...Cutting 3 3 4 4 4 2.2 Plasma Arc Welding 5 2.2.1 Needle Arc Welding 2.2.2 Keyhole Welding 5 6 3. Applications 8 93.1 Economics 4. Environmental Aspects of...Arc Lengths III. Needle Arc Welding Conditions IV. Keyhole Welding Conditions v. Chemical Analyses of Plates Used - vii - 1. 2. 3. 4. 5. 6. 7. 8.

  15. Friction Stir Welding Process: A Green Technology

    OpenAIRE

    Esther T. Akinlabi; Stephen A. Akinlabi

    2012-01-01

    Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in the United Kingdom in 1991 for butt and lap welding of metals and plastics. This paper highlights the benefits of friction stir welding process as an energy efficient and a green technology process in the field of welding. Compared to the other conventional welding processes, its benefits, typical applications and its use in joining similar and dissimilar materia...

  16. Weld Nugget Temperature Control in Thermal Stir Welding

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  17. Thermal Stir Welding: A New Solid State Welding Process

    Science.gov (United States)

    Ding, R. Jeffrey

    2003-01-01

    Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

  18. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...... transfer equation under same conditions. It is relative easy tointroduce boundary conditions such as convection and radiation where not surprisingly the radiation has the greatest influence especially from the high temperature regions in the weld pool and the heat affected zone.Due to the large temperature...

  19. Milestones in welding technology

    Science.gov (United States)

    Dolby, Richard E.

    2013-09-01

    Sir Alan's PhD thesis describes his research into cracking during arc welding of armour steels. Throughout his career, he had a strong interest in defects of all types, how they formed in metallic structures and how the larger ones could be detected and sized by non-destructive techniques. He was also vitally concerned with how defects impacted on the engineering integrity of welded structures, particularly the risk of fracture in nuclear plant. This study presents a view of some of the major milestones in global welding technology that took place over the 60 or more years of Sir Alan's career and highlights those where he had a personal and direct involvement.

  20. Development and evaluation of SUS 304H — IN 617 welds for advanced ultra supercritical boiler applications

    International Nuclear Information System (INIS)

    Pavan, A.H.V.; Vikrant, K.S.N.; Ravibharath, R.; Singh, Kulvir

    2015-01-01

    At moderately high temperature sections of Advanced Ultra Super Critical (AUSC) boilers, welding of superalloys to austenitic steels is inevitable owing to economic aspects of boiler. Welding of SUS 304H and Inconel 617 (IN 617) was attempted using IN 617 filler material employing conventional Gas Tungsten Arc Welding (GTAW) process and the procedure was successfully established along with optimized welding parameters. Microstructural characterization was carried out to identify various zones on either side of the fusion boundaries. Unmixed Zone and Heat Affected Zone (HAZ) were observed towards SUS 304H fusion boundary while no distinct HAZ was observed towards IN 617 fusion boundary. Micro-hardness profiling indicated decrease in hardness at the HAZ towards SUS 304H fusion boundary. Mechanical properties evaluation at both ambient and elevated temperatures was carried out and data obtained was compared with those of base metals. The tensile strength of the cross weld specimens at high temperatures were observed to be marginally lower than that of IN 617 but significantly more than that of SUS 304H, hence, tolerable. Stress-rupture properties of the cross-weld specimens as tested in this study were found to be intermediate to the base metals’ data, thus, suitable for AUSC power plants' boiler applications. Hence, this work gives an insight into welding procedure establishment, microstructural development, variation of mechanical properties at elevated temperatures and stress-rupture properties of the dissimilar metal welds at elevated temperatures. - Highlights: • Procedure establishment & parameters optimization for fabricating defect-free welds. • Characterization of various zones formed during welding. • Mechanical properties evaluation and comparison with those of base metals. • Influence of various zones formed during welding on mechanical properties inferred. • Understanding long term behavior of welds at elevated temperatures

  1. Development and evaluation of SUS 304H — IN 617 welds for advanced ultra supercritical boiler applications

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, A.H.V., E-mail: pavanahv@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India); Vikrant, K.S.N., E-mail: vikrant@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India); Ravibharath, R., E-mail: rrbharath@bhelrnd.co.in [Welding Research Institute, Bharat Heavy Electricals Limited, Tiruchirapalli 620 014 (India); Singh, Kulvir, E-mail: kulvir@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India)

    2015-08-26

    At moderately high temperature sections of Advanced Ultra Super Critical (AUSC) boilers, welding of superalloys to austenitic steels is inevitable owing to economic aspects of boiler. Welding of SUS 304H and Inconel 617 (IN 617) was attempted using IN 617 filler material employing conventional Gas Tungsten Arc Welding (GTAW) process and the procedure was successfully established along with optimized welding parameters. Microstructural characterization was carried out to identify various zones on either side of the fusion boundaries. Unmixed Zone and Heat Affected Zone (HAZ) were observed towards SUS 304H fusion boundary while no distinct HAZ was observed towards IN 617 fusion boundary. Micro-hardness profiling indicated decrease in hardness at the HAZ towards SUS 304H fusion boundary. Mechanical properties evaluation at both ambient and elevated temperatures was carried out and data obtained was compared with those of base metals. The tensile strength of the cross weld specimens at high temperatures were observed to be marginally lower than that of IN 617 but significantly more than that of SUS 304H, hence, tolerable. Stress-rupture properties of the cross-weld specimens as tested in this study were found to be intermediate to the base metals’ data, thus, suitable for AUSC power plants' boiler applications. Hence, this work gives an insight into welding procedure establishment, microstructural development, variation of mechanical properties at elevated temperatures and stress-rupture properties of the dissimilar metal welds at elevated temperatures. - Highlights: • Procedure establishment & parameters optimization for fabricating defect-free welds. • Characterization of various zones formed during welding. • Mechanical properties evaluation and comparison with those of base metals. • Influence of various zones formed during welding on mechanical properties inferred. • Understanding long term behavior of welds at elevated temperatures.

  2. Welding technologies for nuclear machinery and equipment

    International Nuclear Information System (INIS)

    Kobayashi, Masahiro; Yokono, Tomomi.

    1991-01-01

    The main welding methods applied to nuclear machinery and equipment are shielded metal arc welding, submerged arc welding, MAG welding and TIG welding. But in the last 10 years, in order to improve the reliability required for the welding of nuclear machinery and equipment, the welding technologies aiming at the reduction of heat input, the decrease of the number of welding pass and the automatic control of welding factors have been applied for the main purpose of bettering the quality and excluding human errors. The merits and the technology of narrow gap, pulsed MAG welding and melt-through welding are explained. As the automation of TIG welding, image processing type narrow gap, hot wire TIG welding and remote control type automatic TIG welding are described. For the longitudinal welding of active metal sheet products, plasma key-hole welding is applied. Since the concentration of its arc is good, high speed welding with low heat input can be done. For the stainless steel cladding by welding, electroslag welding has become to be employed in place of conventional submerged arc welding. Arc is not generated in the electroslag welding, and the penetration into base metal is small. (K.I.)

  3. Mechanized hyperbaric welding by robots

    International Nuclear Information System (INIS)

    Aust, E.; Santos, J.F. dos; Bohm, K.H.; Hensel, H.D.

    1988-01-01

    At the GKSS-Forschungszentrum investigations are carried out on mechanized welded test plates produced under working pressure between 10 to 110 bar in breathable TRIMIX-5-atmosphere. The welds are performed by a modified industrial robot, which was adapted in its components to withstand these severe conditions. Variations on the welding parameters were made to maintain a stable arc as well as to provide on indication of the effect of the variables on the mechanical properties of the welded joint. During all tests the robot showed a very good function. Good reliable welds were achieved meeting the requirements according API II04 or BS 4515-1984. (orig.) [de

  4. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  5. Analysis of the competition between brittle and ductile fracture: application for the mechanical behaviour of C-Mn and theirs welds

    International Nuclear Information System (INIS)

    Le Corre, V.

    2006-09-01

    This study deals with the fracture behaviour of welded thin structures in the ductile to brittle transition range. It aims to propose a criterion to define the conditions for which the risk of fracture by cleavage does not exist on a cracked structure. The literature review shows that the difficulties of prediction of the fracture behaviour of a structure are related to the dependence of the fracture probability to the mechanical fields at the crack tip. The ductile to brittle transition range thus depends on the studied geometry of the structure. A threshold stress, below which cleavage cannot take place, is defined using fracture tests on notched specimens broken at very low temperature. The finite element numerical simulation of fracture tests on CT specimens in the transition range shows a linear relationship between the fracture probability and the volume exceeding the threshold stress, thus showing the relevance of the proposed criterion. Moreover, several relations are established allowing to simplify the identification of the criterion parameters. The criterion is applied to a nuclear structural C-Mn steel, by focusing more particularly on the higher boundary of the transition range. A fracture test on a full-scale pipe is designed, developed, carried out and analysed using its numerical simulation. The results show firstly that, on the structure, the transition range is shifted in temperature, compared to laboratory specimens, due to the low plasticity constraint achieved in thin structures, and secondly that the threshold stress criterion allows to estimate simply this shift. (author)

  6. Understanding Friction Stir Welding

    Science.gov (United States)

    Nunes, A. C., Jr.

    2018-01-01

    This Technical Memorandum explains the friction stir welding process in terms of two basic concepts: the concentration of deformation in a shear surface enveloping the tool and the composition of the overall plastic flow field around the tool from simple flow field components. It is demonstrated how weld structure may be understood and torque, drag, and lateral tool forces may be estimated using these concepts. Some discrepancies between computations and accompanying empirical data are discussed in the text. This work is intended to be helpful to engineers in diagnosing problems and advancing technology.

  7. CT images of gossypiboma

    International Nuclear Information System (INIS)

    Jeon, Hae Jeong; Lim, Jong Nam; Choi, Young Chil; Park, Jeong Hee

    1994-01-01

    Surgical sponges retained after laparotomy can cause serious problem if they were not be identified in early state. In these circumstances abdominal CT yields the accurate diagnostic images. The purpose of this report is to present highly indicative findings permitting correct preoperative diagnosis of the gossypiboma. We experienced three cases in which CT showed the images sufficiently characteristic to suggest the correct preoperative diagnosis. We evaluated retrospectively the radiological images of gossypiboma confirmed by operation. Three patients were admitted due to palpable masses. Two female patients had medical histories of cesarean sections and a male patient had been operated due to malignant fibrous histiocytoma, previously. Abdominal CT scan of one case revealed huge ovoid hypodense mass with enhanced peripheral rim. Calcific spots and whirl-like stripes were noted within the lesion. Towel was found in pathologic specimen. CT images of two patients showed well-encapsulated, mixed fluid and soft tissue density mass with several gas bubbles. Surgical sponges were found within abscesses. The authors conclude that these characteristic CT findings and careful histories of surgery are very useful for correct pre-operative diagnosis and permit the guideline for the optimal plan of the surgical treatment

  8. CT images of gossypiboma

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Hae Jeong; Lim, Jong Nam; Choi, Young Chil; Park, Jeong Hee [College of Medicine, Kon-Kuk University, Seoul (Korea, Republic of)

    1994-04-15

    Surgical sponges retained after laparotomy can cause serious problem if they were not be identified in early state. In these circumstances abdominal CT yields the accurate diagnostic images. The purpose of this report is to present highly indicative findings permitting correct preoperative diagnosis of the gossypiboma. We experienced three cases in which CT showed the images sufficiently characteristic to suggest the correct preoperative diagnosis. We evaluated retrospectively the radiological images of gossypiboma confirmed by operation. Three patients were admitted due to palpable masses. Two female patients had medical histories of cesarean sections and a male patient had been operated due to malignant fibrous histiocytoma, previously. Abdominal CT scan of one case revealed huge ovoid hypodense mass with enhanced peripheral rim. Calcific spots and whirl-like stripes were noted within the lesion. Towel was found in pathologic specimen. CT images of two patients showed well-encapsulated, mixed fluid and soft tissue density mass with several gas bubbles. Surgical sponges were found within abscesses. The authors conclude that these characteristic CT findings and careful histories of surgery are very useful for correct pre-operative diagnosis and permit the guideline for the optimal plan of the surgical treatment.

  9. Residual stresses due to weld repairs, cladding and electron beam welds and effect of residual stresses on fracture behavior. Annual report, September 1, 1977--November 30, 1978

    International Nuclear Information System (INIS)

    Rybicki, E.F.

    1978-11-01

    The study is divided into three tasks. Task I is concerned with predicting and understanding the effects of residual stresses due to weld repairs of pressure vessels. Task II examines residual stresses due to an electron beam weld. Task III addresses the problem of residual stresses produced by weld cladding at a nozzle vessel intersection. The objective of Task I is to develop a computational model for predicting residual stress states due to a weld repair of pressure vessel and thereby gain an understanding of the mechanisms involved in the creation of the residual stresses. Experimental data from the Heavy Section Steel Technology (HSST) program at Oak Ridge National Laboratories (ORNL) is used to validate the computational model. In Task II, the residual stress model is applied to the case of an electron beam weld of a compact tension freacture specimen. The results in the form of residual stresses near the weld are then used to explain unexpected fracture behavior which is observed in the testing of the specimen. For Task III, the residual stress model is applied to the cladding process used in nozzle regions of nuclear pressure vessels. The residual stresses obtained from this analysis are evaluated to determine their effect on the phenomena of under-clad cracking

  10. Evaluation of A-1 reactor heavy-water calandria specimens

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1976-01-01

    Container chains with surveillance specimens were placed in two special channels of the core peripheral part to test changes in mechanical properties due to reactor operation of caisson tube material. The specimens were made from the caisson tube material and placed by eight pieces on the outer surface of the containers. The first removed specimens were tested for corrosion losses, tensile strength, and fractured surfaces were then assessed. The changes in strength properties were found to be similar in both base material and welded joints. The corrosion film on surveillance specimens did not practically affect strength properties nor ductility. It was found that the Al-Mg-Si alloy used for the heavy water vessel caisson tubes following stabilization annealing was fully stable at operating temperatures of up to 100 degC. Slio.ht changes in properties can be attributed to the effect of a high neutron dose. Thus, the high radiation and temperature stability of the alloy was confirmed. (O.K.)

  11. Microstructure of Friction Stir Welded AlSi9Mg Cast with 5083 and 2017A Wrought Aluminum Alloys

    Science.gov (United States)

    Hamilton, C.; Kopyściański, M.; Dymek, S.; Węglowska, A.; Pietras, A.

    2018-03-01

    Wrought aluminum alloys 5083 and 2017A were each joined with cast aluminum alloy AlSi9Mg through friction stir welding in butt weld configurations. For each material system, the wrought and cast alloy positions, i.e., the advancing side or the retreating side, were exchanged between welding trials. The produced weldments were free from cracks and discontinuities. For each alloy configuration, a well-defined nugget comprised of alternating bands of the welded alloys characterized the microstructure. The degree of mixing, however, strongly depended on which wrought alloy was present and on its position during processing. In all cases, the cast AlSi9Mg alloy dominated the weld center regardless of its position during welding. Electron backscattered diffraction analysis showed that the grain size in both alloys (bands) constituting the nugget was similar and that the majority of grain boundaries exhibited a high angle character (20°-60°). Regardless of the alloy, however, all grains were elongated along the direction of the material plastic flow during welding. A numerical simulation of the joining process visualized the material flow patterns and temperature distribution and helped to rationalize the microstructural observations. The hardness profiles across the weld reflected the microstructure formed during welding and correlated well with the temperature changes predicted by the numerical model. Tensile specimens consistently fractured in the cast alloy near the weld nugget.

  12. Effect of process parameters on microstructure and mechanical behaviors of friction stir linear welded aluminum to magnesium

    International Nuclear Information System (INIS)

    Rao, H.M.; Ghaffari, B.; Yuan, W.; Jordon, J.B.; Badarinarayan, H.

    2016-01-01

    The microstructure and lap-shear behaviors of friction stir linear welded wrought Al alloy AA6022-T4 to cast Mg alloy AM60B joints were examined. A process window was developed to initially identify the potential process conditions. Multitudes of welds were produced by varying the tool rotation rate and tool traverse speed. Welds produced at 1500 revolutions per minute (rpm) tool rotation rate and either 50 mm/min or 75 mm/min tool traverse speed displayed the highest quasi-static failure load of ~3.3 kN per 30 mm wide lap-shear specimens. Analysis of cross sections of untested coupons indicated that the welds made at these optimum welding parameters had negligible microvoids and displayed a favorable weld geometry for the cold lap and hook features at the faying surface, compared to welds produced using other process parameters. Cross sections of the tested coupons indicated that the dominant crack initiated on the advancing side and progressed through the weld nugget, which consists of intermetallic compounds (IMC). This study demonstrates the feasibility of welding wrought Al and cast Mg alloy via friction stir linear welding with promising lap-shear strength results.

  13. Effect of process parameters on microstructure and mechanical behaviors of friction stir linear welded aluminum to magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Rao, H.M. [Research & Development Division, Hitachi America Ltd., Farmington Hills, MI 48335 (United States); Ghaffari, B. [Research and Advanced Engineering, Ford Motor Company, Dearborn, MI 48121 (United States); Yuan, W., E-mail: wei.yuan@hitachi-automotive.us [Research & Development Division, Hitachi America Ltd., Farmington Hills, MI 48335 (United States); Jordon, J.B. [Department of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Badarinarayan, H. [Research & Development Division, Hitachi America Ltd., Farmington Hills, MI 48335 (United States)

    2016-01-10

    The microstructure and lap-shear behaviors of friction stir linear welded wrought Al alloy AA6022-T4 to cast Mg alloy AM60B joints were examined. A process window was developed to initially identify the potential process conditions. Multitudes of welds were produced by varying the tool rotation rate and tool traverse speed. Welds produced at 1500 revolutions per minute (rpm) tool rotation rate and either 50 mm/min or 75 mm/min tool traverse speed displayed the highest quasi-static failure load of ~3.3 kN per 30 mm wide lap-shear specimens. Analysis of cross sections of untested coupons indicated that the welds made at these optimum welding parameters had negligible microvoids and displayed a favorable weld geometry for the cold lap and hook features at the faying surface, compared to welds produced using other process parameters. Cross sections of the tested coupons indicated that the dominant crack initiated on the advancing side and progressed through the weld nugget, which consists of intermetallic compounds (IMC). This study demonstrates the feasibility of welding wrought Al and cast Mg alloy via friction stir linear welding with promising lap-shear strength results.

  14. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  15. Modelling of plastic flow localization and damage development in friction stir welded 6005A aluminium alloy using physics based strain hardening law

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Pardoen, Thomas; Tvergaard, Viggo

    2010-01-01

    of these zones was extracted from micro-tensile specimens cut parallel to the welding direction. The measured material properties and weld topology were introduced into a 3D finite element model, fully coupled with the damage model. A Voce law hardening model involving a constant stage IV is used within...

  16. Welding method by remote handling

    International Nuclear Information System (INIS)

    Hashinokuchi, Minoru.

    1994-01-01

    Water is charged into a pit (or a water reservoir) and an article to be welded is placed on a support in the pit by remote handling. A steel plate is disposed so as to cover the article to be welded by remote handling. The welding device is positioned to the portion to be welded and fixed in a state where the article to be welded is shielded from radiation by water and the steel plate. Water in the pit is drained till the portion to be welded is exposed to the atmosphere. Then, welding is conducted. After completion of the welding, water is charged again to the pit and the welding device and fixing jigs are decomposed in a state where the article to be welded is shielded again from radiation by water and the steel plate. Subsequently, the steel plate is removed by remote handling. Then, the article to be welded is returned from the pit to a temporary placing pool by remote handling. This can reduce operator's exposure. Further, since the amount of the shielding materials can be minimized, the amount of radioactive wastes can be decreased. (I.N.)

  17. Enhancement of mechanical properties and failure mechanism of electron beam welded 300M ultrahigh strength steel joints

    International Nuclear Information System (INIS)

    Zhang, Guodong; Yang, Xinqi; He, Xinlong; Li, Jinwei; Hu, Haichao

    2013-01-01

    Highlights: ► Normalizing at 970 °C plus quenching and tempering cannot refine the columnar grains. ► Ductility and toughness of conventional quenched and tempered joint are very low. ► An optimum combination of strength and ductility was obtained for the welded joints. ► Intergranular cracked columnar dendritic grains were found on the fracture surface. -- Abstract: In this study, four post-weld heat treatment (PWHT) schedules were selected to enhance the mechanical properties of electron beam welded 300M ultrahigh strength steel joints. The microstructure, mechanical properties and fractography of specimens under the four post-weld heat treatment (PWHT) conditions were investigated and also compared with the base metal (BM) specimens treated by conventional quenching and tempering (QT). Results of macro and microstructures indicate that all of the four PWHT procedures did not eliminate the coarse columnar dendritic grains in weld metal (WM). Whereas, the morphology of the weld centerline and the boundaries of the columnar dendritic grains in WM of weld joint specimens subjected to the PWHT procedure of normalizing at 970 °C for 1 h followed by conventional quenching and tempering (W-N2QT) are indistinct. The width of martensite lath in WM of W-N2QT is narrower than that of specimens subjected to other PWHT procedures. Experimental results indicate that the ductility and toughness of conventional quenched and tempered joints are very low compared with the BM specimens treated by conventional QT. However, the strength and impact toughness of the W-N2QT specimens are superior to those of the BM specimen treated by conventional QT, and the ductility is only slightly inferior to that of the latter.

  18. Ultrasonic inspection of austenitic welds

    Energy Technology Data Exchange (ETDEWEB)

    Tomlinson, J R; Wagg, A R; Whittle, M J [N.D.T. Applications Centre, CEGB, Manchester (United Kingdom)

    1980-11-01

    The metallurgical structure of austenitic welds is described and contrasted with that found in ferritic welds. It is shown that this structure imparts a marked elastic anisotropy in the ultrasonic propagation parameters. Measurements of variations in the apparent attenuation of sound and deviations in the beam direction are described. The measurements are interpreted in terms of the measured velocity anisotropy. Two applications of the fundamental work are described. In the first it is shown how, by using short pulse compression wave probes, and with major modification of the welding procedure, a stainless steel fillet weld in an AGR boiler can be inspected. In the second application, alternative designs of a transition butt weld have been compared for ease of ultrasonic inspection. The effects of two different welding processes on such an inspection are described. Finally, the paper examines the prospects for future development of inspection and defect-sizing techniques for austenitic welds. (author)

  19. Visualization of Spot- welding Resistance

    Directory of Open Access Journals (Sweden)

    Michal Černý

    2016-01-01

    Full Text Available This contribution devotes to monitoring of processes running during joining of steel sheets by incadescent so called point welding using non-destructive trial method – acoustic emission (AE. The joining process is detailed described within experimental measuring from the point of view of metallurgic effects runnig during weld creation (records obtained by means of AE method. It takes into consideration quality of joined steels within welding data of steel producer. Steel welding (determined by chemical composition during mechanical verification and firmness of welds consider results of measurement AE and fracture effect of point joints. The measurement also demonstrates conclusion about connection of metallurgic processes with material wave effects (AE measurement and their impact on firmness of joint at steel with guaranteed welding, difficult welding and at their potential combination.

  20. Quantitative metal magnetic memory reliability modeling for welded joints

    Science.gov (United States)

    Xing, Haiyan; Dang, Yongbin; Wang, Ben; Leng, Jiancheng

    2016-03-01

    Metal magnetic memory(MMM) testing has been widely used to detect welded joints. However, load levels, environmental magnetic field, and measurement noises make the MMM data dispersive and bring difficulty to quantitative evaluation. In order to promote the development of quantitative MMM reliability assessment, a new MMM model is presented for welded joints. Steel Q235 welded specimens are tested along the longitudinal and horizontal lines by TSC-2M-8 instrument in the tensile fatigue experiments. The X-ray testing is carried out synchronously to verify the MMM results. It is found that MMM testing can detect the hidden crack earlier than X-ray testing. Moreover, the MMM gradient vector sum K vs is sensitive to the damage degree, especially at early and hidden damage stages. Considering the dispersion of MMM data, the K vs statistical law is investigated, which shows that K vs obeys Gaussian distribution. So K vs is the suitable MMM parameter to establish reliability model of welded joints. At last, the original quantitative MMM reliability model is first presented based on the improved stress strength interference theory. It is shown that the reliability degree R gradually decreases with the decreasing of the residual life ratio T, and the maximal error between prediction reliability degree R 1 and verification reliability degree R 2 is 9.15%. This presented method provides a novel tool of reliability testing and evaluating in practical engineering for welded joints.

  1. Synergy of corrosion activity and defects in weld bonds

    Directory of Open Access Journals (Sweden)

    Michal Černý

    2004-01-01

    Full Text Available Presented work evaluates synergism of atmosphere corrosive action and material defects. These defects appear not only during particular technological process of connecting of structural material but also during cooling and up to hundreds hours afterwards. The multiplication of degradation impact of defects in joint welds and heat-affected zone caused by activity of atmosphere acidic medium is simulated in condensation chambers. The verification is realized by use of mechanical uniaxial tension loading and following fractographic and metalgraphic analysis.The metal plasticity is sufficient factor to eliminate thermal stress in tough metal (11 373. This is reflected in more homogenous weld root area (with no cracks. The corrosion influence of environment is in case of such specimens limited to very slight decrease of weld maximum load. The ultimate strength value decreases approximately for 20MPa only in contrast to dramatic strength decrease in case of 11 503 material. Before metalographic examination was observed surprisingly great value of load capacity of spot welds. These welds were not ruptured nor in a single case even during maximum length of corrosion exploitation. The consequent material analysis discovered high qualitative material and strength properties of this kind of joint.

  2. Screen-film specimen radiography

    International Nuclear Information System (INIS)

    Shepard, S.J.; Hogan, J.; Schreck, B.

    1990-01-01

    This paper reports on the reproducibility and quality of biopsy specimen radiographs, a unique phototimed cabinet x-ray system is being developed. The system utilizes specially modified Kodal Min-R cassettes and will be compatible with current mammographic films. Tube voltages are in the 14-20-kVp range with 0.1-1.0-second exposure times. A top-hat type compression device is used (1) to compress the specimen to uniform thickness, (2) to measure the specimen thickness and determine optimum kVp, and (3) to superimpose a grid over the specimen for identification of objects of radiographic interest. The phototiming circuit developed specifically for this purpose will be described along with the modified Min-R cassette. Characteristics of the generator and cabinet will also be described. Tests will be performed on phantoms to evaluate the system limitations

  3. Results from low cycle fatigue testing of 316L plate and weld material

    International Nuclear Information System (INIS)

    Kaellstroem, R.; Josefsson, B.; Haag, Y.

    1993-01-01

    Specimens for low cycle fatigue testing from the second heat of the CEC reference 316L plate and from Tungsten Inert Gas (TIG) weld material have been neutron irradiated near room temperature to a displacement dose of approximately 0.3 dpa. The low cycle fatigue testing of both irradiated and unirradiated specimens was performed at 75, 250 and 450 degrees C, and with strain ranges of 0.75, 1.0 and 1.5%. There is no clear effect of the irradiation on low cycle fatigue properties. For the weld material the endurance is shorter than for plate, and the dependences on temperature and strain range are not clear

  4. Effects of strength mis-matching on the fracture behavior of nuclear pressure steel A508-III welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhengqiang [School of Material Science and Technology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030 (China)]. E-mail: zhuzhq01@sjtu.edu.cn; Jing Hongyang [School of Material Science and Technology, Tianjin University, Tianjin 300072 (China); Ge Jingguo [School of Material Science and Technology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030 (China); Chen Ligong [School of Material Science and Technology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030 (China)

    2005-01-15

    In this paper, according to the nuclear pressure steel A508-III, the effect of strength mis-matching on the fracture behavior was analyzed by fracture mechanics test and the crack tip stress field of three-point bend specimen was analyzed by using finite element analysis method (FEM). The fracture of heat-affected zone (HAZ) was emphasized especially. The results of FEM show that if the under-matching weld was used, the opening stress and stress triaxiality in the vicinity of crack tip would increase for weld-crack specimen, and would reduce for HAZ-crack specimen. This tendency was confirmed by the test results.

  5. Recent Corrosion Research Trends in Weld Joints

    International Nuclear Information System (INIS)

    Kim, Hwan Tae; Kil, Sang Cheol; Hwang, Woon Suk

    2007-01-01

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  6. DNA extraction from herbarium specimens.

    Science.gov (United States)

    Drábková, Lenka Záveská

    2014-01-01

    With the expansion of molecular techniques, the historical collections have become widely used. Studying plant DNA using modern molecular techniques such as DNA sequencing plays an important role in understanding evolutionary relationships, identification through DNA barcoding, conservation status, and many other aspects of plant biology. Enormous herbarium collections are an important source of material especially for specimens from areas difficult to access or from taxa that are now extinct. The ability to utilize these specimens greatly enhances the research. However, the process of extracting DNA from herbarium specimens is often fraught with difficulty related to such variables as plant chemistry, drying method of the specimen, and chemical treatment of the specimen. Although many methods have been developed for extraction of DNA from herbarium specimens, the most frequently used are modified CTAB and DNeasy Plant Mini Kit protocols. Nine selected protocols in this chapter have been successfully used for high-quality DNA extraction from different kinds of plant herbarium tissues. These methods differ primarily with respect to their requirements for input material (from algae to vascular plants), type of the plant tissue (leaves with incrustations, sclerenchyma strands, mucilaginous tissues, needles, seeds), and further possible applications (PCR-based methods or microsatellites, AFLP).

  7. Stress corrosion crack initiation of alloy 182 weld metal in primary coolant - Influence of chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Calonne, O.; Foucault, M.; Steltzlen, F. [AREVA (France); Amzallag, C. [EDF SEPTEN (France)

    2011-07-01

    Nickel-base alloys 182 and 82 have been used extensively for dissimilar metal welds. Typical applications are the J-groove welds of alloy 600 vessel head penetrations, pressurizer penetrations, heater sleeves and bottom mounted instrumented nozzles as well as some safe end butt welds. While the overall performance of these weld metals has been good, during the last decade, an increasing number of cases of stress corrosion cracking of Alloy 182 weld metal have been reported in PWRs. In this context, the role of weld defects has to be examined. Their contribution in the crack initiation mechanism requires laboratory investigations with small scale characterizations. In this study, the influence of both alloy composition and weld defects on PWSCC (Stress Corrosion Cracking in Primary Water) initiation was investigated using U-bend specimens in simulated primary water at 320 C. The main results are the following: -) the chemical compositions of the weld deposits leading to a large propensity to hot cracking are not the most susceptible to PWSCC initiation, -) macroscopically, superficial defects did not evolve during successive exposures. They can be included in large corrosion cracks but their role as 'precursors' is not yet established. (authors)

  8. Effect of Prior Deformation on Welding Microstructure of Steel 304L

    Directory of Open Access Journals (Sweden)

    WU Luo-fei

    2017-01-01

    Full Text Available This subject was raised by an automotive company.Based on the welding design on the curved surface,the effect of prior deformation on the weld structure was studied.Metal active-gas welding was used on the T-joint and pre-deformed plates of austenitic stainless steel 304L to find the proper welding parameters and observe the effect of prior deformation on the microstructure.The proper parameters acquired are:the speed of the torch is 4mm/s,the speed of delivery of welding wire is 2.5m/min and the voltage is 17V.In the T-joint and pre-deformed joint,the weld toes are in the zone with strain of 0% and 30%.In the pre-deformed welding specimen,it was observed that the fusion zone and partially melted zone are narrowed,carbide precipitation and ferrites are found less.In all,the microstructure in the pre-deformed weld joints on 304L is more uniform.

  9. Laser welding study for further development in essential power plant part repairs

    Directory of Open Access Journals (Sweden)

    Isarawit Chaopanich

    2015-06-01

    Full Text Available The objective of this research work was to study the effects of laser welding when compared with shield metal arc welding (SMAW process on the heat input, welded deposit rate, residual stress, distortion, microstructure and micro hardness. The martensitic stainless steel grade 431 specimens were overlay welded with the stainless steel filler metals. From the results, the heat input of 0.26 kJ/mm in laser welding calculated was significantly lower than that of 1.66 kJ/mm in SMAW, and contributed to low level residual stress, minimal distortion, very small penetration depth and heat affected zone (HAZ of less than 100 µm. The micro hardness results indicated that the maximum value from laser welding in the HAZ was 370.2 HV lower than the value from SMAW of 525.5 HV. The welded deposit rate for laser welding was with 26.5 mm3 /min remarkably lower than the rate for SMAW of 1,800 mm3 /min.

  10. Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

    Science.gov (United States)

    Looney, Alan

    1991-01-01

    Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

  11. Oxide induced corrosion on the welded stainless steels SS 2352 and 2353

    International Nuclear Information System (INIS)

    Stroem, S.; Li Huiqin.

    1991-01-01

    The pitting corrosion properties have been investigated in welded and unwelded condition by polarization tests in sodium chloride solutions. The two steels were TIG welded without adding welding material and as shielding on the bottom side argon gas containing 2, 26 or 99 ppm oxygen was used. In some tests low breakthrough potentials were received, without discovering any pitting corrosion in the specimen surfaces. The unwelded SS 2352 steel had a critical (lowest) pitting temperature (CPT) of 5 degrees C in the more concentrated solution. For the same steel with weld pitting corrosion was obtained at 5 degrees C, which was the lowest temperature for the tests. Thus the CPT value was lower than 5 degrees C, but by looking at the pitting corrosion potentials the following conclusion could be drawn: Welding with higher oxygen content in the shielding gas implied lower pitting corrosion resistance. For the SS 2353 steel the CPT values were 25 and 27.5 degrees C for material without weld, in contact with the more concentrated and the more dilute solution respectively. Welded material was all through more sensitive to pitting corrosion, and the CPT values were 15-17.5, 15 and 5-10 degrees C for welded areas which had been gas shielded with argon containing 2, 26 and 99 ppm oxygen respectively. The result thus showed that welding with shielding gas containing maximum about 30 ppm oxygen does not substantially affect the pitting corrosion properties. Post treatment of the welding areas increased the pitting corrosion resistance. Acid pickling implied the highest pitting corrosion resistance with 15 degrees C as CPT value for the 2353 steel in the more concentrated solution. Steel brushing implied an obvious increase to the pitting corrosion resistance compared to untreated weld areas and the same statement could be done for sand blasted surfaces. (10 refs., 16 tabs., 11 figs.)

  12. 49 CFR 192.225 - Welding procedures.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding procedures. 192.225 Section 192.225... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.225 Welding procedures. (a) Welding must be performed by a qualified welder in accordance with welding procedures...

  13. Integrated sensors for robotic laser welding

    NARCIS (Netherlands)

    Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F; Ostendorf, A; Otto, A.

    2005-01-01

    A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

  14. ICT diagnostic method of beryllium welding quality

    International Nuclear Information System (INIS)

    Sun Lingxia; Wei Kentang; Ye Yunchang

    2002-01-01

    To avoid the interference of high density material for the quality assay of beryllium welding line, a slice by slice scanning method was proposed based upon the research results of the Industrial Computerized Tomography (ICT) diagnostics for weld penetration, weld width, off-centered deviation and weld defects of beryllium-ring welding seam with high density material inside

  15. Sensor integration for robotic laser welding processes

    NARCIS (Netherlands)

    Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Ostendorf, A; Hoult, A.; Lu, Y.

    2005-01-01

    The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process,

  16. Numerical analysis of weld pool oscillation in laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jung Ho [Chungbuk National University, Cheongju (Korea, Republic of); Farson, Dave F [The Ohio State University, Columbus (United States); Hollis, Kendall; Milewski, John O. [Los Alamos National Laboratory, Los Alamos (United States)

    2015-04-15

    Volume of fluid (VOF) numerical simulation was used to investigate melt flow and volumetric oscillation of conduction-mode pulsed laser weld pools. The result is compared to high speed video stream of titanium laser spot welding experiment. The total simulation time is 10ms with the first 5 ms being heating and melting under constant laser irradiation and the remaining 5 ms corresponding to resolidification of the weld pool. During the melting process, the liquid pool did not exhibit periodic oscillation but was continually depressed by the evaporation recoil pressure. After the laser pulse, the weld pool was excited into volumetric oscillation by the release of pressure on its surface and oscillation of the weld pool surface was analyzed. The simulation model suggested adjusting thermal diffusivity to match cooling rate and puddle diameter during solidification which is distinguishable from previous weld pool simulation. The frequency continuously increased from several thousand cycles per second to tens of thousands of cycles per second as the weld pool solidified and its diameter decreased. The result is the first trial of investigation of small weld pool oscillation in laser welding although there have been several reports about arc welding.

  17. Deconvoluting the Friction Stir Weld Process for Optimizing Welds

    Science.gov (United States)

    Schneider, Judy; Nunes, Arthur C.

    2008-01-01

    In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

  18. Welding in nuclear engineering

    International Nuclear Information System (INIS)

    1982-01-01

    The 3rd international conference 'Welding in nuclear engineering', organized in 1978 by the Deutscher Verband fuer Schweisstechnik e.V., was, like the two foregoing conferences in 1970 and 1974, an absolute success. The noteworthy echo to this meeting in the international technical world - the number of 650 participants from 26 countries is self-evidence - and this fact, was for the Deutscher Verband fuer Schweisstechnik e.V. occasion and at the same time an obligation now to follow in the same way, the meeting that was started 12 years ago, by organizing the international conference 'Welding in nuclear engineering'. The conference this year offers in addition to the two plenary session lectures, 34 short reports and a further 28 single contributions in the form of two poster-sessions. Unfortunately, it was again not possible to accept all the papers submitted because the conference was limited to 2 days only. Nevertheless, the papers will offer a representative cross-section through the total range of welding engineering. In particular, the poster session, which take place for the first time within the scope of a meeting organized by the Working Group 'Welding in Nuclear Engineering', should contribute to the aim that this time again the discussions will form the main point of the conference. (orig./RW) [de

  19. Welding. Student Learning Guide.

    Science.gov (United States)

    Palm Beach County Board of Public Instruction, West Palm Beach, FL.

    This student learning guide contains 30 modules for completing a course in welding. It is designed especially for use in secondary schools in Palm Beach County, Florida. Each module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information sheets, student self-check…

  20. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Studies of the transient temperature fields and the hereby induced deformations and stressses in a butt-welded mild steel plate modelledrespectively in 2D plane stress state (as well as plane strain state) and in full 3D have been done. The model has been implemented in the generalpurpose FE...

  1. State Skill Standards: Welding

    Science.gov (United States)

    Pointer, Mike; Naylor, Randy; Warden, John; Senek, Gene; Shirley, Charles; Lefcourt, Lew; Munson, Justin; Johnson, Art

    2005-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide occupational skill standards. The standards in this document are for welding programs and are designed to clearly state what the student should know and be able to do upon completion of an advanced high-school program. The writing team determined that any statewide…

  2. Elementary TIG Welding Skills.

    Science.gov (United States)

    Pierson, John E., III

    The text was prepared to help deaf students develop the skills needed by an employed welder. It uses simplified language and illustrations to present concepts which should be reinforced by practical experience with welding skills. Each of the 12 lessons contains: (1) an information section with many illustrations which presents a concept or…

  3. Effect of current and travel speed variation of TIG welding on microstructure and hardness of stainless steel SS 316L

    Science.gov (United States)

    Jatimurti, Wikan; Abdillah, Fakhri Aulia; Kurniawan, Budi Agung; Rochiem, Rochman

    2018-04-01

    One of the stainless steel types that widely used in industry is SS 316L, which is austenitic stainless steel. One of the welding methods to join stainless steel is Tungsten Inert Gas (TIG), which can affect its morphology, microstructure, strength, hardness, and even lead to cracks in the weld area due to the given heat input. This research has a purpose of analyzing the relationship between microstructure and hardness value of SS 316L stainless steel after TIG welding with the variation of current and travel speed. The macro observation shows a distinct difference in the weld metal and base metal area, and the weld form is not symmetrical. The metallographic test shows the phases that formed in the specimen are austenite and ferrite, which scattered in three welding areas. The hardness test showed that the highest hardness value found in the variation of travel speed 12 cm/min with current 100 A. Welding process and variation were given do not cause any defects in the microstructure, such as carbide precipitation and sigma phase, means that it does not affect the hardness and corrosion resistance of all welded specimen.

  4. Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

    International Nuclear Information System (INIS)

    Rafiqul, M I; Ishak, M; Rahman, M M

    2012-01-01

    It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.

  5. Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

    Science.gov (United States)

    Rafiqul, M. I.; Ishak, M.; Rahman, M. M.

    2012-09-01

    It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.

  6. Effect of Heat Exposure on the Fatigue Properties of AA7050 Friction Stir Welds

    Science.gov (United States)

    White, B. C.; Rodriguez, R. I.; Cisko, A.; Jordon, J. B.; Allison, P. G.; Rushing, T.; Garcia, L.

    2018-05-01

    This work examines the effect of heat exposure on the subsequent monotonic and fatigue properties of friction stir-welded AA7050. Mechanical characterization tests were conducted on friction stir-welded specimens as-welded (AW) and specimens heated to 315 °C in air for 20 min. Monotonic testing revealed high joint efficiencies of 98% (UTS) in the AW specimens and 60% in the heat-damaged (HD) specimens. Experimental results of strain-controlled fatigue testing revealed shorter fatigue lives for the HD coupons by nearly a factor of four, except for the highest strain amplitude tested. Postmortem fractography analysis found similar crack initiation or propagation behavior between the AW and HD specimens; however, the failure locations for the AW were predominantly in the heat-affected zone, while the HD specimens also failed in the stir zone. Microhardness measurements revealed a relatively uniform strength profile in the HD group, accounting for the variety of failure locations observed. The differences in both monotonic and cyclic properties observed between the AW and HD specimens support the conclusion that the heat damage (315 °C at 20 min) acts as an over-aging and a quasi-annealing treatment.

  7. Ti–6Al–4V welded joints via electron beam welding: Microstructure, fatigue properties, and fracture behavior

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoguang [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Co-Innovation Center for Advanced Aero-Engine, Beijing 100191 (China); Li, Shaolin [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Qi, Hongyu, E-mail: qhy@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Co-Innovation Center for Advanced Aero-Engine, Beijing 100191 (China)

    2014-03-01

    The effect of microstructural characteristics on the fatigue properties of electron beam-welded joints of forged Ti–6Al–4V and its fracture behavior were investigated. Tensile tests and fatigue tests were conducted at room temperature in air atmosphere. The test data were analyzed in relation to microstructure, high-cycle fatigue properties, low-cycle fatigue properties, and fatigue crack propagation properties. The high-cycle fatigue test results indicated that the fatigue strength of the joint welded via electron beam welding was higher than that of the base metal because the former had a high yield strength and all high-cycle fatigue specimens were fractured in the base metal. Although the joint specimens had a lower low-cycle fatigue life than the base metal, they mainly ruptured at the fusion zone of the joint specimen and their crack initiation mechanism is load-dependent. The fatigue crack propagation test results show that the joint had a slower crack propagation rate than the base metal, which can be attributed to the larger grain in the fusion zone.

  8. Welding, Bonding and Fastening, 1984

    Science.gov (United States)

    Buckley, J. D. (Editor); Stein, B. A. (Editor)

    1985-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  9. Galvanic corrosion of beryllium welds

    International Nuclear Information System (INIS)

    Hill, M.A.; Butt, D.P.; Lillard, R.S.

    1997-01-01

    Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl - solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed

  10. In-field Welding and Coating Protocols

    Science.gov (United States)

    2009-05-12

    Gas Technology Institute (GTI) and Edison Welding Institute (EWI) created both laboratory and infield girth weld samples to evaluate the effects of weld geometry and hydrogen off-gassing on the performance of protective coatings. Laboratory made plat...

  11. Perspectives of special welding methods. 1

    International Nuclear Information System (INIS)

    Herden, G.; Buness, G.; Wiesner, P.

    1976-01-01

    Laser, electron, ion, and light beam welding as well as plasma arc welding are considered to be special fusion welding methods. The stage of development and possible future applications of these methods are described. (author)

  12. Improvements in and relating to welding

    International Nuclear Information System (INIS)

    Taylor, B.D.

    1979-01-01

    This invention concerns apparatus for use in welding, particularly welding which must be effected in a predetermined, for example, inert atmosphere, e.g. the welding of reactive materials such as zircaloy, titanium, magnesium, aluminium, etc. (U.K.)

  13. Welding for the CRBRP steam generators

    International Nuclear Information System (INIS)

    Spalaris, C.N.; Ring, P.J.; Durand, R.E.; Wright, E.A.

    1979-01-01

    The rationale for selecting weld design, welding procedures and inspection methods was based upon the desire to obtain the highest reliability welds for the CRBRP steam generators. To assure the highest weld reliability, heavy emphasis was placed on the control of material cleanliness and composition substantially exceeding the requirements of the ASME Code for 2-1/4Cr--1Mo. The high tube/tubesheet weld quality was achieved through close material control, an extensive weld development program and the selection of high reliability welding equipment. Shell and nozzle weld fabrication using TIG, MIG, and submerged arc procedures are also being controlled through precise specifications, including preheat and postheat programs, together with radiography and ultrasonic inspection to ascertain the weld quality desired. Details of the tube/tubesheet welding and shell welding are described and results from the weld testing program are discussed

  14. Effect of processing conditions on residual stress distributions by bead-on-plate welding after surface machining

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Mochizuki, Masahito

    2014-01-01

    Residual stress is important factor for stress corrosion cracking (SCC) that has been observed near the welded zone in nuclear power plants. Especially, surface residual stress is significant for SCC initiation. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and residual stress distribution due to surface machining is varied by the subsequent butt welding. In previous paper, authors reported that residual stress distribution generated by bead on plate welding after surface machining has a local maximum residual stress near the weld metal. The local maximum residual stress shows approximately 900 MPa that exceeds the stress threshold for SCC initiation. Therefore, for the safety improvement of nuclear power plants, a study on the local maximum residual stress is important. In this study, the effect of surface machining and welding conditions on residual stress distribution generated by welding after surface machining was investigated. Surface machining using lathe machine and bead on plate welding with tungsten inert gas (TIG) arc under various conditions were conducted for plate specimens made of SUS316L. Then, residual stress distributions were measured by X-ray diffraction method (XRD). As a result, residual stress distributions have the local maximum residual stress near the weld metal in all specimens. The values of the local maximum residual stresses are almost the same. The location of the local maximum residual stress is varied by welding condition. It could be consider that the local maximum residual stress is generated by same generation mechanism as welding residual stress in surface machined layer that has high yield stress. (author)

  15. Studies on mechanical properties, microstructure and fracture morphology details of laser beam welded thick SS304L plates for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Buddu, Ramesh Kumar, E-mail: buddu@ipr.res.in [Fusion Reactor Materials Development and Characterization Division, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Chauhan, N.; Raole, P.M. [Fusion Reactor Materials Development and Characterization Division, Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Natu, Harshad [Magod Laser Machining Pvt. Ltd, Jigani, Bengaluru 560105 (India)

    2015-06-15

    Highlights: • CO{sub 2} laser welding of 8 mm thick SS304L plates has been carried out and full penetration welds fabricated and characterized for mechanical properties and microstructure details. • Welded samples have shown tensile properties comparable to base indicating good weld quality joints. • Impact fracture tests of weld zone and heat affected zone samples have shown poor toughness compared to the base metal. • SEM analysis of fracture samples of tensile and impact specimens indicated the complex microstructure features in weld zone and combined ductile and brittle fracture features. • Combined features of dendrite and cellular structures are observed in weld microstructures with narrow HAZ and delta ferrite is found in the welds and further confirmed by higher Ferrite Number data. - Abstract: Austenitic stainless steel is widely used structural material for the fabrication of the fusion reactor components. Laser welding is high power density process which offers several advantages over the other conventional processes like Tungsten Inert Gas welding. The features like low distortion, narrow heat affected zone, deep penetration in single pass, good mechanical properties are some of the advantages of laser welding process. The laser weld process parameters optimization has several challenges in terms of overcoming the weld defects like voids due to lack of penetration over depth, undercuts and porosity. The present paper reports the studies carried out with CO{sub 2} laser welding of 8 mm thick austenitic stainless steel SS304L plates and their characterization of mechanical properties, microstructure and fracture morphology details. The weld process parameter optimization towards defect free welds with full penetration welding has been carried out. The welded samples have shown tensile properties comparable to base metal, bend tests are successfully passed. The hardness measurements have shown slightly higher for weld zone compared to base metal

  16. Studies on mechanical properties, microstructure and fracture morphology details of laser beam welded thick SS304L plates for fusion reactor applications

    International Nuclear Information System (INIS)

    Buddu, Ramesh Kumar; Chauhan, N.; Raole, P.M.; Natu, Harshad

    2015-01-01

    Highlights: • CO 2 laser welding of 8 mm thick SS304L plates has been carried out and full penetration welds fabricated and characterized for mechanical properties and microstructure details. • Welded samples have shown tensile properties comparable to base indicating good weld quality joints. • Impact fracture tests of weld zone and heat affected zone samples have shown poor toughness compared to the base metal. • SEM analysis of fracture samples of tensile and impact specimens indicated the complex microstructure features in weld zone and combined ductile and brittle fracture features. • Combined features of dendrite and cellular structures are observed in weld microstructures with narrow HAZ and delta ferrite is found in the welds and further confirmed by higher Ferrite Number data. - Abstract: Austenitic stainless steel is widely used structural material for the fabrication of the fusion reactor components. Laser welding is high power density process which offers several advantages over the other conventional processes like Tungsten Inert Gas welding. The features like low distortion, narrow heat affected zone, deep penetration in single pass, good mechanical properties are some of the advantages of laser welding process. The laser weld process parameters optimization has several challenges in terms of overcoming the weld defects like voids due to lack of penetration over depth, undercuts and porosity. The present paper reports the studies carried out with CO 2 laser welding of 8 mm thick austenitic stainless steel SS304L plates and their characterization of mechanical properties, microstructure and fracture morphology details. The weld process parameter optimization towards defect free welds with full penetration welding has been carried out. The welded samples have shown tensile properties comparable to base metal, bend tests are successfully passed. The hardness measurements have shown slightly higher for weld zone compared to base metal and the

  17. Upgrading weld quality of a friction stir welded aluminum alloys AMG6

    Science.gov (United States)

    Chernykh, I. K.; Vasil'ev, E. V.; Matuzko, E. N.; Krivonos, E. V.

    2018-01-01

    In the course of introduction of FSW technology into the industry there is a keen interest in this process; there are issues such as how does joining take place, what is the structure of the joint, and where there are dangerous zones. The objective of this research is to obtain information about the structure of the joint, what are the temperatures that arise during the joining, what strength is apply to the tool when joining the material, what tensile strength of joint, and where fracture tended to occur. Specimens were produced at different modes of welding at a tool rotation speed of 315 to 625 rpm and tool travel speed of 40 to 125 mm/min. During the experiment, the strength applied to the tool was measured, which reached 800016000 N (Fz) and 400-1400 N (Fx) and the temperature on the surface of the tool, which is in the range 250-400°C. Before the welding process the tool was heated to a temperature in the range of 100-250 degrees, but the tensile strength is not had a tangible impact. The tensile strength is about 80 % of that of the aluminum alloy base metal tensile strength, and fracture tended is occur not at the line of joint but follow the shape of the tool. In the transverse cross section of a FSW material there is a microstructural regions such as weld nugget, thermomechanically affected zone and heat-affected zone with parent material.

  18. Developments in welding and joining methods of metallic materials

    International Nuclear Information System (INIS)

    Pilarczyk, J.

    2007-01-01

    The impact of the welding technology on the economy development